For convertable car seats (which I don’t plan on buying for a while, as I want to use an infant seat with base as long as possible) Britax appears to be THE recommended brand. However, it comes with a fairly hefty price tag. (Around $260.) The Marathon model, however, has such tall top slots for the harness that a kid can easily use the seat until they are 5 or 6 (depending on height, of course). So it could be a worthwhile investment.

In the lower price range, the Cosco Scenera ($40-$60) comes with a lot of positive reviews. Minimal padding, but reviews say the kids don’t really notice it. But because of the height of the top slots, kids will probably outgrow this seat by 2 1/2 or so (so you’d still have to buy another seat afterwards).

The Fisher Price Safe Voyage Deluxe is made by Britax, costs about $180, and is pretty good as well. Not sure about height though.