I like achievements, it's fun to get and some are an extra reason to hone your skills in a given game... But I agree they're by no means the sole reason to play games...
Examples as to why here [http://www.vgcats.com/comics/?strip_id=258], here [http://www.duelinganalogs.com/comic/2008/09/22/easily-unlocked/], here [http://www.duelinganalogs.com/comic/2008/04/29/my-greatest-achievement/] and there [http://www.duelinganalogs.com/comic/2007/11/29/and-i-am-an-overachiever/]
Dingo> It's not fixed at 1000, the number can increase with game updates adding new achievements, see Kane & Lynch, Bioshock, etc.