I am correct in thinking that this is both socket AM3 and AM2+ compliant? I'd also like to overclock it so I'd need something better than the stock cooler, something like the "Arctic Cooling Freezer Xtreme Socket 775, AM2, AM2+, 939 Processor Cooler" - http://www.ebuyer.com/product/150981
Motherboard - I don't really know, an AM2+ ATX - advice would be greatly appeciated
Ram - 4gb DDR2 of some sort, again advice would be appreciated.
Graphics - Now here is the crux of the matter, I currently have an Arctic Power 500 - http://www.compucase-hec.co.uk/psu_arctic_power_500-600... and I'd like to keep it if possible. I know most graphics cards require 2, 6 pin molex connector, the psu has one and two spare 4 pin molex and I know it is possible to get an adaptor.
The graphics card should be good enough to play games at 1680x1050 or 1920x1200 as I currently have a 22" inch 1680x1050 monitor which developed dead pixels, and I'm possibly getting a refund, which means that I would get a 24" monitor.
I'm unsure of what graphics card would be best, though maybe a radeon 4850 512mb or 4870 512mb.
for the graphics card, pay the extra for the 1GB 4870 as the 512MB version is absolutely dire at 1920x1200/1080.
so that's £130 so far, I'd get a 550w corsair PSU aswell for £70 just to be on the safe side.
now, a phenom II 550 for £80, and we're at £280, then the ASUS M4A78T-E for £100, so we're at £380, and £48 for 2x2GB of OCZ platinum 1333mhzC7 AM3 optimised, and we're at £428, so a bit over your budget.
The small price difference will end up taking a turn against the AM2/DDR2 build next time you upgrade, as you'll also need to buy a set of DDR3 RAM and possibly an AM3 motherboard.
I would suggest looking around for a Xigmatek Dark Knight cooler. One of the best air coolers around, and they are quite cheap, but eBuyer doesn't appear to have them. If you're only buying from eBuyer, the best heatsink you can get from there accoding to FrostyTech is the Zalman CNPS9700: http://www.ebuyer.com/product/120876
See this is what I dont get, all these people saying the 4870512 will struggle a bit on 1680x1050. I am ordering a new computer myself later today but right now I am using an old pentium 2.6D with 2gig of OK RAM and a 8600GT. With this lot I am getting easily playable frames rates on COD4 etc. Granted this is a year old game but I was expecting a vast improvement by switching over to a phemom 2 x3 4gig RAM and a 4770. But these replies indicate that might not be the case?