I'm in the same boat as you see
:-
http://www.avforums.com/forums/showt...60#post5522860
After bitter experience on e-bay if you want to get all those bits for £50 each you may be very dissappointed.
DDR2 ram is cheap-ish
You can get 2 x 512 DDR2 PC5400 ram for around £14 + postage.
You can get 2 x 512 DDR2 PC6400 ram for around £18 + postage.
But be careful not get in to a bidding war other wise you will pay more or loose out as people go mental on there to "win".
If you spend £50 on ram on e-bay you can easily get around 4gb DDR2 PC6400 but shop around on e-bay to get the best deal.
Hard drive ...... go to places like novatech.com you get a new 200 gb one for around £30.
Graphics card if your happy with the current one then leave it and save some money.
If want a new-ish one start off with getting a 256mb Gforce 7600 GT if get in to a bidding war you can get that 2nd hand for around £25-£30-ish.
Motherboard will be a huge headache you should get one with 1333 FSB, 3 PCI slots and enough connectors at the back to allow you to plug in your existing hardware, but getting this 2nd hand off e-bay is an utter mine field.
The trend now is to sell 2nd hand motherboards which look " ok and new " but have not been tested by the seller, so no one knows if they work or not, you have a 50/50 chance of buying a good or bad one. On top of that they have no warranty, no money back option and most have no manual, no software, no cables nothing but the bare motherboard.
If you get a bad one you cant send it back so you've lost all your money. But e-bay buyers are going crazy and are paying close to or higher than new motherboard prices for some thing which may or may not work........
This is utter madness............but people don't care and push prices up of things which should sell for peanuts (coz thats all they are worth).
You could get one off private seller but again people will go bidding mad and your £50 budget will be blown and you may get some thing which isnt that good.
Better to get a new one off ebuyer for £50 see
:-
http://www.ebuyer.com/product/132269
Thats the one i'm saving up to get as that has all the bits i need + i dont have to pay rip off e-bay prices for 2nd hand stuff with no warranty.
Asus are also a very good make.
You will need to get a 500 or 600 watt PSU.
CPU will be the most expensive thing you get, wait 3-6 months and you should get a decent new one for around £100 which is now around £150-£200.
Get the E6600 or its equivalent.
Word of caution they are now talking about DDR3 ram and 1600 FSB CPUs so what ever you get now will be out of date in 6 - 12 months time, bear this in mind when working out what you want.