I have 3 and 5 year old boys. The car seat we purchased 4 years ago for my oldest was a Cosco. It was the smallest 5 point harness seat available at babies-r-us, inexpensive and had one of the highest safety ratings on the market.
We had a Jetta at the time and needed a small car seat. It has been durable, easy to install and uninstall, and space-saving. My 3 year old has had two good years in it so far.
It isn't fancy, (no cup holders or excessive cushioning) but it fills the bill quite nicely.
Good luck with your search. It is great when they can finally face forward. Happy birthday to yur little one!
C.