Some general ideas:
The knight party:
PC Cavalier
Keldorn
Mazzy
Anomen
Nalia (noblewoman)
Imoen (damsel in distress)
The Holy Liberator (from the Oversight mod):
PC Holy Liberator (install BGTutu or BGT)
rest of party as the "default" members from BG1 (Imoen, Jaheira, Khalid, Minsc, Dynaheir), and not replacing them when they do not show up in BG2 (and add ToB NPC, just to make it complete).
Solo Monk:
extra points for doing it on insane with Tactics and Ascension...
Chaotic party:
CN Wild Mage
Minsc
Jan
Anomen
Korgan
Haer'dalis (and later ToB NPC, if you choose)
"Snake in the Grass":
Install the Virtue mod, then play an evil guy. Try your best to get your rep up to 20, while trying to keep your Virtue rating as low as possible (do evil things and still come out smelling like roses...)
"Walking the Line":
Install the Neutral Trials mod. Play the game doing your best to keep your rep between 8 - 12 all game, and do your best to "keep the balance" at all times. Extra points for using a certain longsword as your favorite weapon.
Humor party:
PC Jester
Minsc
Jan
Edwin (best if you install the Happy Party mod)
Korgan
Viconia
Just throwing stuff out as it came to mind, just to give you some ideas. Hope that helps!