[KarmaKiller]

Wow, I'm surprised your keeping all your hair through out this!

Ok, so basically we need to find you:
skt 775 motherboard
good heatsink
case

That's easily done.
Newegg.com - GIGABYTE GA-P31-ES3G LGA 775 Intel P31 ATX Intel Motherboard - Intel Motherboards
+
Newegg.com - ARCTIC COOLING Freezer 7 Pro 92mm CPU Cooler - CPU Fans & Heatsinks
+
Newegg.com - COOLER MASTER Centurion 5 CAC-T05-UW Black Aluminum Bezel , SECC Chassis ATX Mid Tower Computer Case - Computer Cases
(^has free shipping)

That will get you a VERY durable and stable motherboard. The heatsink was enough to cool my overclocked quad core, and is near silent, so that will work out great for you.
And the case is a solid case, with some fans that come pre-installed, and will be plenty big enough for what you need.

Edit:
Also wanted to mention that motherboard supports some faster CPU's, so when you feel the need to upgrade, you can.