Well, it depends on what your goal is with regard to having the software. I use Mozilla because <b>I want it to get better</b>. If I use it and fill out the bug reports, send in crash info, etc, they will use it to make it better. If I used Netscape or Konq or whatever, Mozilla doesn't get better. As it is, I think Mozilla is the best browser on Linux anyway, but that's really just a nice bonus and not my main motivation.
Maggie - Use the binaries from
http://www.nvidia.com when you upgrade instead of going with what RedHat ships. Well. If you play 3D games, anyway. I don't believe RedHat ships the NVIDIA drivers - actually, I'm positive of it. The only non-open software they ship is Netscape Communicator, and they're looking to ditch that pretty soon.
As for dist-upgrades, you shouldn't have any problem unless you're like me and muck with all sorts of things to make your system run *exactly* how you want it to. I am stupid and do this. Therefore, once I have an install in place, I cannot ever do a dist-upgrade, because it will break things. That's okay - I upgrade things as I see fit. Every once in a while I might kill everything except my home partition and start again fresh with whatever the latest is. But generally I just leave it be and take care of things by hand. This tends to work well.