I don't care much about achievements these days but I'm still highly interested in reputations - specifically, reaching exalted. I have a way to go before I actually have 40 exalted reputations myself, as I missed out on a few for various reasons: low rep in vanilla raiding, not much TBC/WotLK raiding, and not enough PvP; and these days I only play 5-10 hours per week, which makes finding time for anything other than heroics or dailies almost impossible.
Check this guy's reputation out. I've seen people with a lot of exalted factions but have a look at his Bloodsail rep. Pretty insane, huh?
I intend to get around to doing Dire Maul runs for Steamwheedle rep. When Cata hits, I'm hoping that more people will run DM; which in turn should reduce the price of Libram of Protection; at which point, I want to finish grinding my Shen'dralar rep.