While I'm not the greatest with spells, I do have a list I keep - here are some thoughts from that:
Spells worth preparing
1
Charm Person
Obscuring Mists
Silent Image
2
Detect Thoughts
Glitterdust
Minor Image
3
Whispercast
Dispel Magic
Dimension Step
4
Evard's Black Tentacles
Mirror Image, Greater
Ruin Delver's Fortune
Solid Fog
Celerity
Freedom of Movement
Invisibility, Greater
Minor Creation
spike stones
Thunderlance
5
Draconic Polymorph
Arcane Fusion
Dimension Shuffle
Wall of Force
6
Starmantle
Antimagic Field
Power Word: Nauseate
Spells that you can recall if needed (either typically non-combat, or in a buff sequence when you know what you face)
1
Alarm
2
Rope Trick
Close Wounds
Heroics
Heroism
3
Mass Conviction
Spark of Life
Anticipate Teleportation (or greater)
Arcane Sight
Clairaudience/Clairvoyance
Greater Mage Armor
Greater Mightly Wallop
Phantom Steed
Protection From Energy
4
Ethereal Mount
Death Ward
Sheltered Vitality
Contingent Energy resistance
Death Ward
Greater Scying
Voice of the Dragon
5
Permanent Image
Persistent Image
6
Reflective Disguise, mass
nixie's grace
It would probably be useful to prepare a few lists of spells for easy reference:
* spells to prepare
* spells for all-day buffing (1 hr/lvl)
* spells for buffing before dungeons (10min/lvl)
* spells for buffing before combat when you have warning (1 min/lvl)
* specialty spells that you'll often use, but won't prepare
.... or some such.
Best,
David