Kernel not recognizing your hardware? Problems with power management or PCMCIA? What hardware is compatible with Gentoo? See here. (Only for kernels supported by Gentoo.)
firefox has a "feature" where it never frees memory from pages you visit, it keeps them so you can go forward / backward in your history quickly (at least I think that's why it does it). There's plenty of discussion on the web about it, try googling.
As far as mysql is concerned, the memory usage is controlled by the /etc/mysql/my.cnf option file. You can tweak this here, although I think if you add up everything you allocate there, it can still use slightly more than that.
Not sure about the others, though.
Well, the Sister was right. You boys could use a little churching up. Slide on down to the Triple Rock, and catch Rev. Cleophus. You boys listen to what he's got to say.