Hello all- first time poster, short time lurker. I actually just picked up this game and have been playing for about a month now. Played PnP D&D as a kid (over twenty years ago) and I have fallen in love with BG2 and D&D all over again. I can't believe how much I have missed these games. The fact that there are still (very) active message boards for such an old game speaks to the greatness of the title and to the loyalty of its fans. Consider me a convert and thanks for all of the advice!
Now for the question... I am forming a party of characters of my own creation. Inquisitor, Berserker/Cleric, and Sorcerer. I want to add a theif/mage but I can't decide whether to go with a swashy mage or an assassin mage. Any thoughts? Also, does an assassins poison work with mage spells if they are dualed? i.e. I want to poison Melf's AA's in a minor sequencer to devaste opposing mages. Thanks again to all of you.

I think Assassin's "poison weapon" only affects attacks. You could poison Melf's Minute Meteors but not Acid Arrow.

I guess I should mention the this characters primary thieving purpose will be to find and deactivate traps. He will then serve as a secondary defensive mage. I could scout and backstab with the ring and cloak obtained early on, but I'm not sure if I would prefer that over the thieving, AC and melee bonuses of the swashy. Probably leaning toward assassin...

Swash/mage for the skill points. Allows you to dual quicker (lvl 10 is ideal), and even the small AC bonus will be more than you'd get when compared to what you would get for your low assassin levels. You'd have to get up to level 21 as an assassin to get the backstab x7, so that's not worth it. You can still stealth and scout with a swashie, you just don't get the backstab. Plus you can specialize in quarterstaff and two-handed weapon style just in case the enemy gets too close.

I've got a swash/mage in my BoM party, and even though she hasn't dualled yet (I'm waiting for lvl 15 for even more skill points and an extra to hit/damage/AC bonus) she's still pwning with a staff and Tuigan bow. :evil:

I think part of the allure of the assassin was to poison spells like magic missle to fight mages. Am I making too much of this ability?

Go for multiclass. It sucks having to wait for your thief levels to be reactivated. Once you have played a couple of times and know which quests do not have any serious traps and a great XP gain, save these for your transition period. Gnome Thief/Illusionists are perhaps the best multiclass Thief/Mage out there.

@trask2:
It's been said already, but you can't poison spells, only weapons. Some spells (like Melf's Minute Meteors, Ghoul Touch, etc.) make weapons that you can then poison, but that's the limit.

Welcome -- I also played the early pnp games. And then all the gold box editions, and now all the games listed in SP....

First, have you played through with single protagonist, picking up party members along the way? The real strength of the game is the interactions between the characters. The writers really outdid themselves in this game and having as many npc's in the party as possible really adds to the game. Every one of the npc's has interactions with each other -- and most have quests. The combination of you (sorcerer), Keldorn (inquisitor), Anomen (fighter/cleric), Jan Jansen (illusionist/thief) is one of the funniest in the game. If you are female, Anomen will have a romance with you, if male, I would recommend taking Jaheira (the fighter/druid is quite powerful).

That said, I tend to roleplay. An inquisitor and assassin are opposite ends of the spectrum. So I would recommend a swashbuckler (Errol Flynn type Robin Hood character) to fit with the paladin. However, the swashbuckler will not have a backstab -- so if that's important to you don't pick swashbuckler. The bounty hunter (Yoshimo) is a good choice as it doesn't have the extreme penalties the assassin has (15 points per level is tough).