What's a good, smaller, low to medium heat producing graphics card from 2010?

My case is kind of small, and my power supply isn't exactly beastly. But it was able to run an ATI radeon HD 4890 for 2 years with relatively few problems, except in the summer. It only broke down once while the warranty was still active, but it's went and died on me. My power supply wasn't really having any problems running it, I just had to keep the windows open and the fan on. It was quite nice during the winter. Kept my room at a toasty 80 degrees when it was 15 degrees outside and I had the windows open all the way and the fan was on. Anyway, I suppose it's time to upgrade. I've got about 370 dollars to spend right now, I figure that should be more than enough for my needs. But I'm looking for a slightly smaller GPU in the 200-300 dollar price range. The big problem I have is that there are so many video cards that came out this year, so I'm not sure what to choose.