Both EverQuest and EverQuest II let players choose deities for their characters. This feature's primary purpose in the first EverQuest was facilitation of role-playing, but in EQ2 a player's choice of deity (a feature added in the Echoes of Faydwer expansion) has gameplay implications as well. It's a really cool idea which was born in the old text MUD days but which finds only rare application in modern games.
For those who play EQ2 and want to explore Norrath's vast pantheon of deities, Ten Ton Hammer has a terrific guide. It lists all the deities with descriptions and lists of their alignments, the quests you can do in their names, and the miracles they'll grant you.
Walk with Mithaniel Marr, my friend.