I would also reccomend using only one of your characters and filling all other spots with NPCs. their interaction is one of the best parts of the game, I'd be a shame to miss out on your first play through.
also, I'd reccomend having either Jaheira, Aerie or Viconia in your party since you can have a romance with one of them (or have two or all three of them... and laugh when they start fighting over you

)
since you wanted a paladin, monk and an archer for your characters, I reccomend you play a monk. there is a very good paladin in the game, who is also IMHO one of the most useful NPCs. as for the archer bit, there is a fighter, Mazzy, who's got grandmastery in short bows. monks get some great bonuses and with their magic resistance work wonders on enemy spellcasters. also they have excelent THAC0 and AC, together with final 4 attacks/round they're great in melee combat.
now for some info on non-evil NPCs:
- Keldorn, an inquisitor. has True Sight and Dispel Magic abilities which make him basicaly a must-have for any good aligned party. paladins are also the only ones who can wield the most powerful weapon in SoA.
- Minsc, a ranger. he makes a good tank, gets some druid spells and has a hamster

a very fun character, though not the brightest
- Valygar, a stalker. he comes with proficiency slots spent on katanas, which are the most powerful single handed weapons, unfortunately there are but two or three of them actually worth having. but one of them is still very near the top of the 'best weapons list'. he can also backstab if you bother with it.
- Mazzy, a fighter. as said, she specializes in short bows and there is a very good short bow out there that doesn't need ammo! she should be interesting to you since you wanted an archer.
- Jaheira, multi-class fighter/druid. her biggest problem is, there are no really good weapons for her to use until quite late in the game. other than that she's a good healer and gets some very nice druid spells (summonings, insects...) and can also handle melee combat easily. she's also one of the romance interests and her romance is the longest and most complex of the three, unfortunatelly it's also very bugy and has a tendency to hang-up.
- Anomen, dual-class fighter/cleric. one word - ANNOYING!! most will agree he's the most annoying character of all, at least in the beginning. all would be well if that was the end, but unfortunately he is VERY good at what he does. a great cleric, with improved fighting abilities from his fighter class. can also achive grandmastery and dual-wielding two of the best weapons in a game makes him a very good tank.
- Aerie, multi-class cleric/mage. some hate her, some love her, some find her annoying and whinny, some find her cute

the fact is cleric/mage is a very useful combination, but in SoA the xcap prevents her from achieving very good level in either class. she still gets an impressive array of mage and cleric spells and with proper gear she can also enter melee combat. as mentioned before, she's also one of the romance options, but her romance is the shortest of them.
- Jan, multi-class mage/illusionist. the funniest character in the game, loads of stories and funny remarks. he's a good thief and has a lot of gear that help to even increase his thieving skills. also a decent backup mage.
- Yoshimo, a bounty hunter. the only pure thief in the game, though the penalty from being a bounty hunter reduces his thieving abilities a little. he can lay special traps though. can wield good weapons but bad THAC0 and AC don't make him a good choice for melee combat.
- Nalia, dual-class thief/mage. her thief skills are only very basic as she's only a lvl 4 thief, but she's the best mage for a good party. not much to say, if you want a good mage (alignment- and ability wise) early in the game pick her up.
- Imoen, dual-class thief/mage. her abilities are very similar to Nalia's, but she's a lvl 7 thief and her thieving skills are really enough to get you through the whole game. as a mage she's practically identical to Nalia but since you get her rather late in the game she'll be a little behind most of your party experience wise.
than there are Cernd (druid) and Haer'Dalis (bard, not sure which kit) but I never had either of them in my party, not even for a second, so I can't tell you anything about them.
and I'll let someone else tell you about evil characters, this post is long enough as it is
