Huh, a $100 quadcore ain't half bad, perhaps I should buy one. Looks like it'd be faster than this first gen Core i5 I'm using. Could probably keep the upgrade sub-$250 for RAM/CPU/Motherboard...
What kind of i5 do you have? If its a i5-2500k your only going to gain ~15% to ~20% in performance, I would buy a 1600X or just hold off on upgrading at all.
Huh, might end up going for a higher end chip, but I could definitely use that bump in performance! Already got an SSD, optimized kernel and a few other tweaks to get the most out of this chip, but it only goes so far.