I do suggest:
AMD Athlon 750 Mhz - 1.2 Ghz Processor - Cheaper (don't want to discuss if better) than Intel Processors
Abit, IWill or Asus mobo (Via KT133, Via KT133A or AliMagik 1 chipset)
128-256 Mb of PC133 Brand Name cas 2 SDRAM or DDR-RAM if motherboard supports it (I do suggest Crucial or Mushkin brands)
nVidia Geforce 2 GTS, Geforce 2 Pro or Geforce 2 Ultra graphics cards (I think Guillemot, ELSA, Asus and Creative are good brands); if you are on a tight budget you could buy a Geforce 2 MX, but I think a Power Color Evil Kyro is a better choice
7200 RPM Ultra DMA 100 hard disk drive (IBM, Maxtor, Fujitsu...) - 30 GB is enough...
Toshiba whatever high-speed CDROM drive
Sound Blaster Live! - whatever model, or Guillemot MaxiSound
Good 2.1 speakers, cause you're not likely to make profit from 5.1 speakers, it's up to you
Good case with 300W Power Supply - it's easy to spot a good case
19' Monitor - I do suggest NEC FE 950 - love it, but it's not mine (remember it will last for your next computer)
Acer mechanical keyboard
Logitech cordless optical mouse (or get a Microsoft one, they've got life warranty, but people report they are crap, you can have a new mouse every year though)
Ratpadz mouse surface
Even if you want to use it for gaming, you could get it with a 12x Toshiba DVD-ROM drive (I know Pioneer are faster, but I do hate slot-in drives, and Toshiba work better with scratched or copy protected CD's); another must is a CDRW drive - for example... the Plextor 12/10/32A
If you want to game online, you could get a crappy 56k modem or get cable or DSL from a local provider
Please give us a budget and where you live