If you want stability, security and flexibility out of the box, check out slackware. The install is not as flashy as RH or Mandrake, and you have to manually configure a few more things. However, in the long run I have found it much easier to administrate and configure. Mandrake is the easiest install I have found, but I always have headaches trying to do things like recompile the kernal or get compile software not included. If you wnat a nice wm that behaves similarly to win 9x you might also want to check out icewm. I have gotten KDE 2 running on my slack box, and I really like it in terms of user friendly. Debian I have heard is the easiest to admin because of its apt-get feature and is very stable as well, but I think the install is probably not geared towards newbies.
Check out slck for a server, I don't think you will have any problems with the install if you just follow the directions.
my $0.02