Curse you Glenn Turner! I'm actually in the process of writing an article quite similar to this and must say, have similar ideas.

I'll post you a link when I'm done but I believe we cover different ground.

My main problem with Achievements is the way they affect people playing games. For instance, playing through a game and dropping it after 100% Achievements unlocked and moving onto the next big conquest. I believe they act as a measure to limit a gamers own creativity when playing games, as instead of constructing their own challenges, they may think "oh, this is all I need to do?"

Anyway .. like I said .. link when finished!