I upgraded a few months ago and after getting a few parts for Christmas I thought Ill post what I have now.
I upgraded my CPU from a 4100 to an 8350 (saw heavy changes in performance there),
I upgraded my Cooler Master TX3 (I think it was a TX3) to an H60 (and It looks so nice in my build),
I upgraded from a 7770Ghz edition to a 7970Ghz edition (I am gladly abusing the 7970Ghz by getting the most graphically intense games out there :p and visual mods for skyrim),
I upgraded my crummy Rosewill wifi card to a nice TP-Link WDN4800 (And I couldn't be happier with the performance of it),
I upgraded my PSU (Same Corsair model; different wattage),
and I threw in a couple of fans in there. All in all, I'm pretty happy how it turned out. But now I have my PC part graveyard box where all all my old parts went ;.;. But they will be used in a project for January so its all good.