Any of the mini distro's would work fine and be easier for you to set up.Just running a server w/o anykind of GUI, I dunno, try Basiclinux, its a stripped down version, uses busybox but also allows use of pkgs from slackware 3.5.They also have an updated version of Basiclinux based on slackware 7.1, either would work just fine and give you a good small base to learn how to use linux.Dunno which versions of apache,mysql, or php those come with though, you'd have to check that.Try
http://www.linux.org and click on distributions and do a search.
Any of them will work, and be fairly small with just a server setup.Redhat, Mandrake are very easy to set up but will be a little on the large side, but youve got 10Gb to work with anyway.