We have the Cosco Alpha Omega Elite. It's easy to use, looks nice, and claims to be very safe. Fortunately, we haven't had to test the safety (aka an accident). It can be used as a rear-facing infant seat, a forward-facing car seat, and a booster. I think the weight limit for rear-facing is 30 lbs or so, forward-facing up to 40 lbs, and a booster up to 100 lbs. I may be a little off on the weights, so you may want to check. My son is 43 lbs and we're still using it as a car seat, as the straps still fit. My son hasn't complained once and he's been in it since he was about 10 months old (r-facing) and he's 3 1/2 now. We paid about $180 at Target. Good luck!
mommy of one and one on the way!