If you`ve not tried it before you`ll find it can do many of the things your already doing and more besides (webserver,file/printserver,proxy/cache/firewall, MySQL server etc).
It lets you play with its inner workings much more than MS software if you want to although I admit it takes more effort and understanding sometimes.
Look in the newsagents for a magazine containing the distros there`s usually one or two to be had.
Your best bet would be Mandrake, Suse or Fedora(formally Red Hat).
The latest versions of these will install quite well on most hardware and come with lots of included software to try.
You might also find demo versions that run entirely from the CD.