Everyone in my party has either a composite longbow, a shortbow if a composite longbow isn't allowed, or a sling if that person can't use a bow or carries a shield.
Apart from that, I always have a thief, one or two mages, a cleric or a druid, and the rest rangers and/or paladins.
I shoot at every oponnent first, waiting for them to come to me so I can get as many shots off as possible before I switch to close combat with everyone who chops better than he or she shoots.
My mages will keep shooting along with the thief, unless I deem the enemy enough of a threat to actually use magic (which is rarely). Occasionally, I send in the thief as a 'second wave', and once the enemy is occupied I might throw in my mages as well, but mostly they just stand back whirling their slings.
In BG2 I prefer playing an archer and use hit and run tactics instead, while I lock the rest of my party in a closet so they won't get themselves into trouble
