I'm a bit rusty on PC's. It's been a while since I've had to know about all the parts, so instead of recommending brands/specific items I'll run through each part in order of importance for me.
Feel free to disagree. My knowledge is limited at best, though by following this order I have a PC that kicks arse for its spec.
1)Hard Drive. The Speed is far more important than the size. Also search around for a reliable make (nothing more annoying than a HD buggering up). Maxtor suck. That's about all I know on that one.
2) Motherboard. Must support high-end parts, so you can upgrade later.
3)Processor. In my experience AMD>Pentium even when money is no object. Things may be different now though.
4) Graphics card. I'd read reviews on these. Some can be dodgy, and alot of AMD cards seem to cause bugs in games if your lazy like me and never update your drivers.
5) RAM. It's cheap and easy to get by the bucketload.
6) Case. I know bugger all about cases. They could be the most important part for all I know.
This is the order of importance I followed a few years ago when my dad taught me how to build a PC. It's spec is AMD Athlon 1800+, an 80 gig HD (7200rpm) (can't remember the make, but it's good). 256MB RAM, 32MB Geforce 2 and I can't remember the make. If it weren't for the graphics card it would still hold its own against supposedly better machines. It's still faster than my other PC that has pretty much double the spec (with a pentium 4 2.8GHz processor and a maxtor HD) on windows apps and games that it will actually run.
Even so, I accept no responsibility if you follow my advice and fail. I warn you - my knowledge is severely limited (as I'm sure other members here will testify). I recommend reading up on the subject as much as possible, and make your own decisions.
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