I've checked out Iron (a Chrome variant with the parts removed that phone home to Google), and it was a lot faster -- but I can't live without the many extensions I have collected throughout time for Firefox. And I need some more UI than Iron provides, it seems.
So I poked around a bit and found out that there's a PPA with Firefox 3.6 in it. After a bit of fiddling I now have 'Namoroka' (the codename for Firefox 3.6) running. And so far, it seems a lot faster than 3.5 -- the rendering doesn't block the whole UI anymore, which is important to me. I want to be able to click on a link to open it in a new tab, and then move on. It's how I read my friendspage, and I don't want to wait with scrolling on until the other page in the other tab is finished loading and rendering.
So that seems like a total succes!