Party 1:
Squall (well ya have to , but also coz he's my favourite)
Rinoa (I don't know exactly why but I used to do it just coz they were an item, now its just a habit that i dnt mind sticking to)
Zell (strong+funny+comic relief= )

Party 2:
Squall (as above)
Irvine
Selphie/Quistis....
You know, I think I always have 2 guys in the party :-S