Fixed my safari issue in Lion
First, I gave it the old college try and really tried to get it to work for me (reinstall, removing all extensions, click2flash, opening empty window on new tab, disabling restore windows on open, minimizing tabs open, etc.).
I found the only fix was to move to the bloatware known as Chrome. Sure it eats more memory which is why I never went there in SL, but it doesn't hang my machine even when memory gets down very low and is stable.