I have 35. That's mostly because I only play about 3 civs.
I do care a little about achievements, as it 'forces' you to try out other civs/maps/styles. I can't remember ever playing a native american civ (like Aztecs) in al my tens of thousands of hours I spend playing Civ since '91. Now I will probably give it a try, just to get the achievement. '
On the X360 I go for achievements (in games like Mass Effect) because it forces you to get the most out of the game. Play as a good guy, bad guy, woman, man, etc. Just like in Civ5, with different Civs, maps, wonders, etc.