Safari Crashing

I have a 3.06Ghz 24in imac. Safari crashes a lot. Don't know what to do.

I've reset Safari several times, and downloaded Safari 4 in order to uninstall and reinstall a new Safari 3. Safari version is 3.2.1.
I've reset pram, restarted, and verified permissions several times over.

Crashes happen almost exclusively when multiple windows are open. Other than that, I really am not sure of a pattern. Also, the restore tabs from last browsing session rare restores everything. I guess it's a buggy feature.

Any tips? And please, don't recommend another browser. I also opera 9 and firefox 3. I just really like Safari. Thanks.