Unfortunately the new AMDs are pretty terrible. They draw lots of power and have a hard job beating their own previous gen Phenoms. Intel Sandy and Ivy Bridge CPUs are just much much better. For gaming even the dual-core i3-2100 will beat AMDs chips in most
Since the £30 Asus board I linked to on the last page is now out of stock. You can pair a £47 ASRock H61M
(which has USB3 and SATA 3 to take advantage of SSD) with an Ivy bridge i5-3450 (£150) for the same money as the FX-6100 and have a much better system.
Or Novatech have the i3-2120
for £89, which would give you a marginally better system for £60 less.
Also on the last page I linked to a Z77 board which comes with a Artic 7 CPU cooler. Pair this with an i5-2500K or an i5-3570K and with just a little bit of overclocking, you will have a system that no AMD chip can match.
You'll also need the 8GB of Corsair Vengeance RAM I linked to on the last page. Intel Sandy and Ivy bridge take 1.5V memory whereas your kingstons are 1.65V.
Other advice is to also get a Samsung 830 128GB SSD
If you still have that old HDD around ditch the Seagate HDD as well.
Bit hard to give advice on the GPU front without knowing what games and what resolution you will be playing at, but as grey_matters said the 6850 is very good. 1920x1080 is pretty much the standard res for monitors these days and the 6850 is great for that.
Edited by FutileResistor at 11:38:28 27-06-2012