My main character is a fighter and my party is
1-Nalia:Best good-aligned mage in game specially with her short bow and thievery skills but I like her for her sexy skirt. But if your main character is a mage, take Keldorn or Valygar for Nalia.
2-Anomen:Great good-aligned cleric, he's a dual class so he advances level fast and he can be GM in hammer,mace,flail. Also his STR is 18/52. Very though for a cleric.
3-Minsc: I like him, he's funny and though, also he is specialized in dual wielding and more over he can be master in dual wielding.
4-Jan:Great thief with his special items and skills and also he makes you LOL
As 5th character you can have Jaheira or Aerie. I picked Aerie because she's so cute and her romance is very enjoying also she's a good spellcaster with her spell quantity. But her HP is low and she's weak in melee but I use her in ranged combat.
For Jaheira, she's got a romance also and her INSECT PLAGUE spell is wonderful. If you want a druid in your party and also fighting abilities she can be a good choice. Give her a girdle of hill giant strength and she will be a good fighter.