help spec me a pc

[Scoped]

hi guys, i've got a few questions that i need a little help with

so the budget is £500,
for a mobo, cpu, ram, hdd, monitor

I have a 9800gt green edition gpu and a Enermax Liberty 500W Modular PSU (will this be good enough to power a new set up?)

I want to make a reasonable gaming rig

so here are my questions:

should i go intel or amd?

depending which one, what processor model and mobo model should i be looking at?

and for windows, does the oem edition mean i cant upgrade the computer in future?

thanks for your time

 

[Scoped]

thanks guys!

is the 2500k a good processor if you don't over clock it?
(would there be a big step up between the i3 you mentioned and the 2500k)

and if i buy one should i buy retail with the included hs or buy oem and buy a £20 heatsink?

for ram would this be an improvement Corsair Vengeance Blue 8GB (2x4GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (CMZ8GX3M2A1600C9B) [CMZ8GX3M2A1600C9B]

or a worthwhile improvement anyway?

also with that ram do the heatspreaders cause any problems in terms of fit?

for the monitors - I really don't know too much about them, but is the 8,000,000 to 1 ratio a true representation compared to the iiyama?

thanks so much for your time guys!

 

[Scoped]

thanks for all your help guys,
I'm going for the 2500k retail (in case i don't overclock)
the 2 * 4gb corsair and the gigabyte board

thanks very much for all your help, it should come tomorrow, i'll let you know how it goes!