i run a core 2 cuo and a quad xeon besid eachother but before i owned a more than single core cpu had an athalon xp of some sort that still works to this day and a 1.86ghz celeron which fried out a few months ago we have another 2.4ghz celeron pc that still works but it's the familys. i have a ton or working cartridge processors (2x 450mhz P3, 1or 2 450 mhz P2, 330mhz celeon, 300mhz celeron and i had at some point a 220mhz processor)
I had an AMD Athlon 64 AM2 Dual running at 4600mhz.
Now I have a Skulltrail motherboard which can take 2 Quad cores Ug Ug Ug More power lol.
So it has 2 x Intel Xeon E5472 running at 3GHz, 8GB of RAM and 2 x GTX 280's. We even updated the internet speed at our home so now I also have 8Mb Broadband too which is great. I can't wait for the release of Win7 on the 22nd.