TentacleMayor: What? For a lot of people they can provide motivation to play the game again, possibly in a different way, or to focus on something else rather than just getting to the ending. That's replay value.
Hickory: No they don't. Once you've got the achievements, you've got them, however you play the game. Playing again to get the same achievements is an exercise in idiocy.
Replay value does not necessarily mean
infinite replay value. Pre-achievement era, games attempted (still do, of course) to add replay value by having multiple viable playstyles. You could play Deus Ex in a few different ways, but once you did all of them that was it, you'd seen everything. Achievements give you reason to do even more, it's an easy way to incentivize unorthodox gameplay that you normally wouldn't try because there's no reward involved. Yes it's for collectors but it doesn't have to be for everyone and can be turned off.
And no, just because a game is good doesn't mean it automatically has a lot of replay value. Especially if it's linear. Metro 2033 was good and all but I can't say I was reaching for the New Game button to do it all over again, in the same order, as soon as the credits rolled.
