Ninja/spellthief or pure spellthief level 6

[CommCrab]

So just yesterday in our campaogn my argent was cleaved in two on his horse by a frost giant. Now I am on need of a new character and I really like the look and possibilities that a spellthief presents, however we also have no rogue in the party. Thus I am tossing up between a dual ninja 3/spellthief 3 or a straight spellthief 6. It is a faerun campaign with about 8 PC's quite a few spell casters, and we have come up against a fair few magic users so no worries there. The main tossup was with the ninja I was thinking level 3 would allow me to have the use of poison without the chance of poisoning myself, plus ghost step which would allow the charcter to ninja their way into position for a sneak attack. My main reason for coming here was thoughts on the two possibilities and very keen on suggestions (as this would be my first multiclass) and then as such decent feats and race to play? All suggestions are very warmly welcomed.  Thanks!

[altpersona]

http://www.giantitp.com/forums/showthread.php?44299-Jack-Of-All-Trades-Fax-Celestis-Guide-to-Spellthieves

[TML]

Note that 'steal spell-like ability' is crazy good provides you have SLAs available to tap.  It prevents people from using the ability for a couple minutes, but it doesn't reduce your uses/day.

So if you have a warlock in the party, get all the 24 hour buffs you want.  Grab any 1/day SLAs possessed by anyone in your party.  It takes a standard action (no attack roll or anything) to grab from a willing target, which makes it pretty straightforward. 

Not necessarily useful for in-combat (without swift action spells), but there's a ton of possible buffs and utility - especially if you team up with a factotum.

[CommCrab]

Cheers for the responses. Sadly no warlock however we do have a cleric, wizard and two others whose class I am not really sure of (they were off doing somwthing else during our fight).
However the main thing I was looking for was advice as to whether 3 levels in ninja would be a viable/worthwhile build for the ghost and poison use, as well as sudden strike, to increase sneak damage/make it easier to sneak. That plus the possibility to put another two levels into the class to end up with ki dodge, and acrobstoc jump. The main issue I can see is the inability to wear armour or I would lose the use of those powers, however it may be worth it overall? Just not completely sure being jew to the whole thing.

[zook1shoe]

PrCs available? Tome of Battle?

I wouldn't split classes between ninja and spellthief

[CommCrab]

No ToB, and not sure about PrC's. After a bit more thought devised bit to ninja dual and just pure spell thief for now,  maybe later with a dip into duskblade to channel spells, but will do some mpre reseaech to see how well that would work.