I'm having a bit of bother with Flash Player 10.1 on Mac OS X 10.6.4 using Safari 5.0.2 and Firefox 3.6.10. In the last couple of days, every time I visit GMail with the Flash plug-in installed in /Library/Internet Plug-ins, the browser freezes, beachballs and has to be force-quit. Removing the Flash plug-in cures the problem, and having only the Flash plug-in installed will trigger the problem, so it's not a conflict. The same problem seems to occur with the BBC iPlayer, though some websites that use Flash (YouTube, for example) seem to work just fine.
I've tried un-installing and re-installing Flash, clearing caches in Safari, downloading Firefox to see if it's broken there too, repairing permissions and all the other placebos I know, but nothing has made any difference. I'm suspicious of it being a corrupt setting or cache file that's knocking Flash over (it works fine on all the other similarly-configured Macs I use) - where does it keep its user files? Other troubleshooting suggestions are most welcome.
[edit] Thank you to all those who've suggested ClickToPlugin and similar, however it's not really a solution - while I've no idea why GMail wants Flash, I'm experiencing this problem with sites that require Flash, such as the iPlayer