If it's done well, I don't mind it. The GTA4 ones, or DQ9, would be good examples. But if it's just a costume, or launched same day as the game, or adds stuff that could be in some people's multiplayer but not others, then no. More often than not, it's done poorly, so I lean toward no, but I have to vote that it really depends.
-dunno001
-On a quest for the truly perfect game; I don't think it exists...