Need some help with my Wizard/Spellthief

[RotIF]

I'm going to be rolling a Human Wizard4/Spellthief1 for an upcoming 3.5 campaign and I need some guidance on what feats/spells/prestige classes would be best to take. I've chosen Transmutation as my specialty school barring Enchantment/Necromancy and our current party consists of a Ranger, a Druid, a Barbarian, and a Swashbuckler if that helps.

[Biffoniacus_Furiou]

What do you want this character to do? It looks like you're trying to make a Wizard who can find and disarm traps, if that's the case then consider something like a Beguiler 1/ Wizard 4/ Ultimate Magus instead. The rest of your party should be more than capable of dealing damage in combat, so you don't really need sneak attack and this will give you far more utility and more options in general. Check out this post I made (http://www.giantitp.com/forums/showthread.php?296176-Ultimate-Magus-Is-it-any-good#4) on the subject.

[RotIF]

Well I'm going to be the main arcanist for the party, I mostly took Spellthief for flavor, and I thought it would be a neat choice because its an interesting class. Also, we will be fighting a lot of mages.

[Biffoniacus_Furiou]

Well I'm going to be the main arcanist for the party, I mostly took Spellthief for flavor, and I thought it would be a neat choice because its an interesting class. Also, we will be fighting a lot of mages.

Spellthief isn't much better than anything else at fighting enemy spellcasters, especially with only a single level in it. Beguiler gets Silence as a 2nd level spell, which you can cast centered on a point in space to automatically prevent them from casting spells with verbal components. You can even ready an action to cast that after they've started casting to automatically interrupt their spell if it has a verbal component, no matter what level it is, so it's even better than counterspelling. Versatile Spellcaster will allow you to spend two 1st level Beguiler spell slots to cast that even with only one level of Beguiler.

[RotIF]

While Beguiler certainly seems like a good choice, I have my heart set on Spellthief. Stealing other caster's spells just seems to fun to give up.

[gorfnab]

Spellthief 1/ Wizard 5 (Spontaneous Divination ACF)/ Unseen Seer 10/ Arcane Trickster 4 - Feats of note: Craven, Practiced Spellcaster, Master Spellthief

Sneak Attacking Spellcasters Handbook (http://brilliantgameologists.com/boards/index.php?topic=1240)

[Biffoniacus_Furiou]

While Beguiler certainly seems like a good choice, I have my heart set on Spellthief. Stealing other caster's spells just seems to fun to give up.

"At any one time, a spellthief can possess a maximum
number of stolen spell levels equal to his class level (treat
0-level spells as 1/2 level for this purpose)."

The feat Master Spellthief allows you to steal higher level spells, but with only one level of Spellthief you'll only be able to benefit from stealing 1st level spells. Any spells higher than 1st are still stolen from the target, but they will simply go away because it would cause you to exceed the maximum number of spell levels you can steal.

With that in mind, Unseen Seer in Complete Mage and Arcane Trickster (http://www.d20srd.org/srd/prestigeClasses/arcaneTrickster.htm) are probably your best choices of prestige classes.

[RotIF]

Thanks for the help so far, does anyone have any suggestions for my spell list?