bler144: I tend to like achievements when they are creative, or humorous, and esp. if they can prompt you to really approach a game or an encounter or a skill differently than you would if 'beating' it was the only point.
If, on the other hand, they are things you would normally do anyway in the course of completing the game, I'm not sure they're worth much.
But worst are achievements that are pure grind and zero thought/skill, clearly intended just to fill space and/or waste time.
Pretty much sums up my own thoughts on it.
There are, I think, three games on Steam for which I have all the achievements, and I got those because I played those games a lot and enjoyed them.
Deus Ex: Human Revolution, for instance, has the kind of achievements I dislike (getting to certain points in the story, which you'd do anyway if you don't just quit the game halfway through), but it also has some interesting ones - playing through Missing Link without ever upgrading anything, which was an interesting challenge and fun to play. In that sense, at least the existence of the achievement made me do something fun I'd never have thought of on my own.
So basically, I don't care much, but sometimes achievements can make games more interesting in a way.
(Meanwhile,
Grow Home has an achievement for drowning like 5 sheep. No way in hell I'm doing that!)
I do sometimes compare achievements with friends on Steam out of curiosity, but I'm not competitive in general, so seeing someone with an achievement I don't have won't motivate me to go and get it.