Hope this will help some people. My Safari suddenly became very slow to launch, and started giving beachballs a lot. The fix I finally found is easy--and several other people have said it works for them too: Empty out the Icons folder in your user's Library/Safari folder. Start Safari up and all should be well. No need to throw out prefs, Reset, repair permissions, or re-install Safari. I've heard some very painful fixes for this problem--and they usually include throwing out a lot more than necessary. The culprit seems to be a bug regarding the favicons (the little icons on bookmarks). That Icons folder stores the favicons of the places you've visited. It can grow to several MB--but whether that's what triggers the bug I cannot say. After doing this, your bookmarks will have generic icons. But don't worry, as you visit your bookmarks, each icon will return.