I've been trying for years, it's difficult to impossible to spend a year or even half a year without spending anything, and the financial stress gets worse when you move to the next year of education. In theory if you believe you can save around £800, you can build a very component machine that will last you through a few years before it begins to show it's age seriously.
As for a build, the best PC builders I have ever come across is DinoPC. I cannot recommend these guys strongly enough, their PCs are always up to date, unbeatable on price (I hate this term but damn are they difficult to match) and their customer service is excellent.
http://www.dinopc.com/shop/pc/pcs-gaming.asp?idcategory=94
As for a suggested build, Overclockers UK, dabs, aria and scan are all the sites you should need. They're usually the most comprehensive and competitive on price. Make sure you research each component individually before buying so as not to just trust the run down on the sales page.
£800 Budget -
Asus Crosshair IV Formula AMD 890FX (£167) - When and if you upgrade to crossfire, this AM3 800 board will support full 16x 16x channels for both cards or 16x 8x 8x in 3-way crossfire. It supports USB 3.0 and SATA-III as all 800 boards do, has excellent onboard sound control from a SupremeFX X-Fi chip, and is all round a versatile mobo.
AMD's Phenom II X6 1090T (£150) - Unlocked multiplier and six cores clocked at 3.00Ghz for under £200. It's a great gaming chip with lots of headroom for overclocking. Alternatively you could go X4 and save a bit of money, however don't pay a premium for an extra 200Mhz, the overclocking ease on these chips negates the need completely.
G.Skill RipJawsX 4Gb PC-12800 (£50) - Great latency timings, 1600Mhz clocked, all round good RAM but if you look around you might find cheaper. Try to keep the combined timings of the latencies as close to the final number as possible but simultaneously low, for example these modules are 7-8-7-24 timed. Always buy branded RAM with a good warranty.
ATI Radeon 6950 1Gb (£188) - More than decent card, under £200. I don't know what else to say about this card, I recommend just taking some time to learn about how a GPU works and then what's currently on the market (I mean you have the time
).
1Tb 7200RPM 64Mb Cache SATA-III (6Gb/s) ideally. Western Digital Caviar Black do one for about £72. Very reasonable if you ask me. Ignore SSD for now.
Optical drives wise, you don't need Blu-Ray but it's nice to have. If you think you can afford it, maybe go for it if you intend to watch Blu-Ray films. Don't strecth yourself to get one though, they're not necessary at this point. A good DVD±RW will do, the LiteOn IHAS124 is around £15.
Coolermaster GX 650W PSU (£60) - Never go cheap on a PSU, it's possibly the most crucial part of your entire system. If it seriously fails, everything seriously fails. You cannot afford not to get a trusted brand, high efficiency (80% and up) with lots of adaptability. This PSU delivers all that with a hefty 650W to keep everything running smoothly, supports crossfire set ups, has 100,000 hours MTBF and runs of a single +12V rail (look this up).
Finally (sort of) the case. Antec 300, Coolermaster HAF or Coolermaster Storm Scout. I'd go Antec 300, you just can not go wrong with it, a legendary case. Really
You're going to want a 64bit OS, but what you choose is up to you. An OEM Windows 7 Home Premium 64bit will set you back about £80, it's a good OS as you'll be well aware, professional is better but comes with the price tag. I don't think you'll want to go Linux if this rig is for gaming, but their are competent Linux gaming platforms growing as we speak, so keep an eye out.
This'll all change over the year but for now it holds true as a staple of a good £800 rig, and would last you a good half decade before it even began to show age. The RAM would do well to be upgraded at some point to 8Gb, and as previously mentioned it's all prepared for a 16x 16x crossfire set-up. Whether you choose to stick with the 6950 or have moved onto the 7*** series by then is your call.
Hope some of this helped.
