Primary Classes Should help in determination what type of character does primary
Secondary Classes now because gestalt takes two classes and combines two classes to this is where all classes have things that can add to enhance a character some does that more than other so I will list the Class and the strengths that the class can bring and some examples of applying them.
Warning the Next Wall of Text will hurt some people eyes
[spoiler]
Note : Did not list any NPC classes or variants and if I had forgotten any sorry it may be added later.
NOTE = most of these are the option of the other and I have been wrong in the past. And a apologise now if I do say something about a classes that people like
Archivist = and intelligent based divine class that has access to any divine spell very good with combined with the wizard.
Artificer = artificer is very good at making and using magic items and can cast any spell in the game
Barbarian = Strength and Constitution bonuses, fast movement, and a d12 hit die. Over all very useful for Gish builds
Bard = need more research or exparance for option on this class in this class
Crusader = One of the best tank classes in the game
Druid = I will have to argue that this is one of the most powerful classes in the game.
Duskblade = The duskblade can cast in armour, A d8 hit dice and full BAB make obtain familiar/improved familiar viable feat choices not bad over all as a secondary class
Dead Necromancer = need more research or exparance for option on this class in this class
Factotum = One of the Best Skill monkeys in the game best combined with any class that needed a High intelligence Score.
Favoured soul = Very Good Spell list and weapon focuses feat ling
Fighter = Useful Feats and One of the Better Non magic damage dealing classes in the game best use in making a tank or an archer (not both at the same time). Commonly used in tank and grish builds
Healer = well they get some healing spells and gate spell as well as a Unicorn companion it has to be good for something right ?
Hexblade Full BAB D 10 HD a good spell list very useful as a secondary class.
Incarnate = need more research or exparance for option on this class in this class
Knight = Bulwark of Defense is very only problem there is a Maneuver that does the same thing
Lurk = need more research or exparance for option on this class in this class
Monk = bonus feats, full saves, and Wis to AC, For an extra bit of mobility Only good in Enlightened/Sacred fist type Gishes,
Ninja = few very cool class abilities descent skill monkey, over all the Swordsage can do the same and at times better then the Ninja.
Paladin = I think we can save a lot of time and argument in just using the crusader instead.
Psion = very good casters. but like the Wizzard and Scorcer have nova issues
Psychic warrior = need more research or exparance for option on this class in this class
Ranger = five bonus feats a good spell list good very good synergy with the Scout
Rogue = a solid class Trap finding, Trap Sense, high Reflex, (Improved) Evasion, Search and Spot lead the rogue to be the go to trap finder, and with the right equipment a very useful class
Samurai = full BAB, d10 HD & good Fortitude-save. It also has Sense Motive and Diplomacy in class as notable advantages over Fighter but limited in fighting styles
Scout = Very Good ranged class with good mobility and trap finding bust mixed with the Ranger.
Shaman= need more research or exparance for option on this class in this class
Shugenja = need more research or exparance for option on this class in this class
Sorcerer = very useful spontaneous caster with full caster levels
Soulknife = It's "magic" weapon scales slower than normal magic weapons, over all it is not a good class.
Spellthief = good spell list and can steel spells very useful with the Duskblade or hexblade
Spirit shaman = need more research or exparance for option on this class in this class
Swashbuckler = very good with other Gishes builds
SwordSage = weakest Martial Adapt but very good for grish builds. Or when mixed with either the Crusader or War blade for a very powerful tank
Warblade = Arguably one of the Best Melee classes in the game with D12 HD full BAB and But there is some problems no ranged attack and the highest type of armour is Medium
Warlock = many SLA options that are useful in a secondary class. But also is useful with prisms and other caster that can were armour is useful when combined with a caster class you you have a bad hobbit of not using good spell disabling the Eldritch blast will have more use
Warmage = very flexible few save-or-die and battlefield control spells, can cast in armour this is class that gets better with Rainbow Servant
Wilder = see Prism
Wizard = Full casting and is your Standard Caster class
[/spoiler]
FIFY. No, seriously.
[spoiler]
Note: I did not list any NPC classes or variants. If I have forgotten any, I'm sorry. They may be added later.
NOTE = Most of these are the option of the other. (Editor's note: I tried on that last sentence, but couldn't make heads or tails of it.) I have been wrong in the past. I apologize if I say something bad about a class that people like.
Archivist = an Intelligence-based divine casting class that has access to any divine spell. Very good with combined with Wizard.
Artificer = Artificer is very good at making and using magic items and can use those items to cast any spell in the game.
Barbarian = Strength and Constitution bonuses, fast movement, and a d12 hit die. Very useful for Gish builds.
Bard = I need more research or experience with this class to understand the options available for it.
Crusader = One of the best tank classes in the game.
Druid = This is
one of the most powerful class
es in the game.
Duskblade = The Duskblade can cast in armor. It has a d8 hit dice and full BAB. This class makes Obtain Familiar and Improved Familiar viable feat choices. Not bad, overall, as a secondary class.
Dead Necromancer = I need more research or experience with this class to understand the options available for it.
Factotum = One of the Best Skill monkeys in the game. Works best when combined with with a class that needs a high Intelligence score.
Favored Soul = Very good spell list and Weapon Focuses feat.
Fighter = Useful feats and one of the better non-magic damage dealing classes in the game. Best used in making a tank or an archer, though not both at the same time. Commonly used in tank and gish builds.
Healer = Gets some healing spells and the Gate spell, as well as a unicorn companion. It has to be good for something, right?
Hexblade = Full BAB, d10 hit die, and a good spell list. Very useful as a secondary class.
Incarnate = I need more research or experience with this class to understand the options available for it.
Knight = Bulwark of Defense is good. The only problem is that there is a martial maneuver that does the same thing.
Lurk = I need more research or experience with this class to understand the options available for it.
Monk = Bonus feats, full saves, and Wis to AC. Good for an extra bit of mobility. Only good for Enlightened/Sacred Fist-type gishes.
Ninja = A few cool class abilities, and a decent skill monkey. The Swordsage can do the same things, and do them better then the Ninja.
Paladin = I think we can save a lot of time and argument by just using the Crusader instead.
Psion = Very good "casters." Like the Wizard and Sorcerer, they have nova issues.
Psychic Warrior = I need more research or experience with this class to understand the options available for it.
Ranger = Five bonus feats and a good spell list. Has synergy with the Scout.
Rogue = A solid class. Trap-finding, Trap Sense, high Reflex save, (Improved) Evasion, Search and Spot enable the Rogue to be the go-to trap-finder. With the right equipment, this is a very useful class.
Samurai = Full BAB, d10 hit die, and a good Fortitude save. It also has Sense Motive and Diplomacy as class skills. Some might consider these advantages over Fighter. On the other hand, it is limited in its fighting style.
Scout = Very good, highly mobile class. Has Trap-finding. Best when mixed with the Ranger.
Shaman = I need more research or experience with this class to understand the options available for it.
Shugenja = I need more research or experience with this class to understand the options available for it.
Sorcerer = Very useful spontaneous caster, with a full 9 spell levels.
Soulknife = It's "magic" weapon class feature scales slower than normal magic weapons. Not a good class.
Spellthief = Good spell list and can steal spells. Very useful with the Duskblade or Hexblade.
Spirit Shaman = I need more research or experience with this class to understand the options available for it.
Swashbuckler = Very good with other gish builds.
Swordsage = The weakest Martial Adapt but very good for gish builds, or when mixed with either the Crusader or Warblade for a very powerful tank.
Warblade = Arguably one of the best melee classes in the game. A d12 hit die, full BAB. Lacks ranged attack options heavy armor proficiency.
Warlock = Many SLA options that are useful in a secondary class. Also useful with Psions and other casters that can wear armor. Is useful when combined with a caster class. You have a bad habit of not using good spell disabling the Eldritch blast will have more use. (Editor's note: again, I tried to work with that last sentence but couldn't figure it out.)
Warmage = Very flexible. Has few save-or-die and battlefield control spells, but can cast in armor. This is a class that gets better with the Rainbow Servant PrC.
Wilder = See Psion.
Wizard = Full casting. This is your standard caster class.
[/spoiler]
I edited for clarity, and less for content.