If you haven't already seen it, go download and install the new public beta of Safari 4. While just a beta, it's WAY faster at rendering pages, the new Top Sites page is cool (if not ripped off from Opera). The new tabbed interface is an improvement, too (tabs are now above the address bar).
NOTE 1: I haven't downloaded or tried the Windows version of this beta, which is available as well.
NOTE 2: If you are using the current version of Growl Notifier (1.1.4) and you install the beta, please be aware that there seems to be a conflict with Mac Mail and the new Safari 4 beta. You need to disable Growl Notifications in your Mail app before installing Safari 4 beta.