Firefox 3.5 has been released! I've been using it since betas and even the final is faster. Especially if you do a clean install.
Fun tweak to enhance speed:
In your address bar enter: about:config
Search for: jit
One will be set to false, ensure both are set to: True
Restart Firefox and enjoy the speed.
Pages are rendering for me in the blink of an eye. JIT is basically the new TraceMonkey that they've been working on.
You can also get it from my Anti-Malware Toolkit.