Considering the 3-4 main types of builds (str vs dex, int vs faith) resulting in a pretty high degree of variability in playstyles from game to game, not to mention the huge array of different sub-categories of spells, items, weapons', special attacks, and so forth; builds are practically endless. It's the only game where you can say "I'm going to play a fistfighter who attacks by shooting chaos fire directly into someone's brain". Yeah, it has quite the replay value.