Odd numbers of fighter levels (except for 1) are almost always bad. You never take levels with 0 class features if you can help it. Usually, for a fighter build in core, you want to take 2 or 4 levels of fighter. Ranger 1/Fighter 4/Deepwarden 5 is probably better and should be doable. If you only want Deepwarden 2, look for another prestige class to take, or fill in odd levels with other classes like paladin or barbarian. Fighter 7 is almost always a bad idea, and 6 or 8 aren't much better in core.
There are 3 generally good fighter options. They are Archer, Battlefield Controller, 2 handed power attacker. Archer and 2 handed attacker do enough damage make monsters notice them, Battlefield Controllers (usually trippers) put the monsters in a position so that they can't hit your wizards.
Weapon + Shield fighters are one level down. The AC bonus they get is not usually equal to the damage they give up. Wielding a 2 handed weapon with a buckler is usually superior.
2 weapon fighting is harder because: 1: You are less likely to hit with all of your attacks when you are taking penalties to hit.
2: (and more important) Most of a fighters damage comes from strength bonus + power attack. You get half your str bonus on your off hand weapon, and you can't power attack with it.
example:
A dwarf with 18 Strength and power attacking for 4 wielding a waraxe 2 handed does
1-10 + 6 (strength x1.5 for 2 handing) +8 (power attack x2 for 2 handing) =1-10+14 Average 19.5
A dwarf wielding the same weapon 1 handed with a shield does
1-10 +4 (strength) + 4 (Power Attack) = 1-10+8 Average 12.5 losing 7 damage per hit
A dwarf 2 weapon fighting with waraxe and hand axe does
1-10 +4 (strength) + 4 (Power Attack) = 1-10+8 and 1-6+2 Average 18 IF he hits with both attacks! He is better throwing his hand axe on the ground and swinging the big axe with both hands.
If you really want to 2 weapon fight, something like Rogue 3, Ranger 2, Deepwarden 5 might do better. The TWF numbers come out much better when you throw in sneak attack damage.
But really, for a fighter build, with a barbarian already in your party who I assume is doing big damage with 2 handed fighting, consider something like Improved trip, Exotic weapon spiked chain, Combat reflexes, Power attack.
Edit: My response was assuming that you wanted a fighter. They are correct. A druid 10 or Cleric of Moradin 10 whips almost any fighter as a melee combatant.
