Which disrto to use?
I picked up a Coolermaster CM-690 for 69 bucks in newegg.com free shipping. Probably one of the best cases for the price considering its fan placement, the amount of fans you can mount in it (about 7 or 8), and the ventilation. It has a solid feel to it as well. All tool-less, and cut outs for liquid cooling. Also an available clear side window for 40 bucks from CM.
As far as the distros go, what has been said so far is what I agree with. While Fedora Core is a good stable OS that can be very powerful when you learn to use it, Ubuntu is very user friendly, and is a great way for someone used to MS Windows to migrate over and explore Linux for the first time. I use Ubuntu as a dual boot from Vista because I haven't used Linux in a few years and forgot a lot.
I believe Fedora Core has RPM files which can install themself (no compiling necessary), and Ubuntu has .deb files which can install themselves. So either way should be a feasible distro if you are new to Linux.