Google Chrome has that speed dial feature from Opera, and I'm digging it. I never used Opera much except for testing, but it's definitely a cool feature now that I'm using it. My big complaint about Opera is that it runs on an older version of gecko (the rendering engine mozilla developed, used in firefox). It's the same version running in Firefox 2, which isn't terrible, but FF3 is faster and less buggy. I guess there's also a way to make Opera use the IE7 rendering engine, which is just gag-inducing.
No Chrome on Linux or Mac yet though, so if speed dial is a must-have feature I'd look for Opera in those OSs. Chrome's other features are pretty badass though if you're running Windows. I have only been using it a day and I already find it's the first browser I go to (out of the six on my task bar I have to keep around for development testing).