If you are into science in any form, or any kind of educational software, Scientific Linux is your best choice. It is put together by the folks at Fermilab in collaboration with the team at CERN, and you would be hard pressed to find a better group of pure scientists on the planet. It has install distro’s, which is where the real power is; the packages you install will determine what all it can do. Right out of the box it comes with Apache installed and ready to run, like any good variant of Enterprise Linux, and it uses the openafs file system, making it fully compatible with most education and research facilities. To start with I recommend going for the Live CD or Live DVD, which you can run right off the disk, without touching your currently installed operating system. That will give you the opportunity to get familiar with the operating system before you decide to install it, as well as give you a collection of office, programming, internet, and multimedia software. If you have an older system you want to install it to, it has the option of using icewm as your desktop rather thane Gnome or KDE, which need a lot more RAM. It is built on top of Red Hat Enterprise Linux, which is an incredibly stable environment. And if you think it is missing some important software, one of the kinds of tool sets it has are things that allow you to install it, install whatever additional software packages you like, and then make your own Live CD, Live DVD, or boot-able memory stick from it, using things like revisor, livecd-tools, or liveusb-creator. The latest version, 6.5, was just released and is ready to be run.