BTW, I haven't seen that either Safari or FF on the Mac (or FF on the PC) get unstable as a result of a large cache. I think the issues with IE may have something to do with all the adware and all that kind of stuff. I only clear out my cache for security / privacy reasons, and not terribly often.
And also FWIW, if you've used IE on a PC, you shouldn't have had that much trouble finding the clear cache option in FF, since it's almost in exactly the same place.
Actually, the problem I have is that when I used my PC, I used Hotmail almost exclusively. About once per quarter, it would shut down on me. Just couldn't get to it. I e-mailed Microsoft and received a reply that had me clean out everything in sight of MSIE. It worked, but it really became a pain to do it. I was always waiting for the problem to resurface. I still have some ties to it, but now use .Mac mail as much as possible. With .mac, some of my e-mails get automatically "junked" until my recipients know I'm using it. Go figure.