Mozilla Firefox 1.5
It's not that good, but it's good. The pages load quick, changing tabs is quick. It generally feels snappier. That could be in part because it's using libcairo now on debian, but I don't think that's all there is to it. Anyway, you may have to add (string) app.extensions.version = 1.0 in your about:config to get all your extensions working, but meh.
There's a search bar on my history. I don't know if it was there before.