Diablo 2

Very, very addictive game. On the surface it looks very similar to the first, and it is. But they made some very nice enhancements to gameplay that made a great game even better. Skill development in particular was nicely tweaked. Multiplayer changes were good and bad; there were 3 different types of characters: single player characters that you could also use online, multiplayer online only, and multiplayer online only "hardcore" (when the character dies they are done). That being said, multiplayer over the modem was sketchy at best. But when it worked, it was a lot of fun. Certain characters work really well together (my necromancer partied well with a friend's paladin).