I would suggest building your own computer, if that is something you would like to look into. It's cheaper, you know what quality parts you're getting, and you'll learn a lot about computers in the process. I built my first one this summer, and it really wasn't very tough at all. Plus, if something goes wrong, you can always come on here and ask
Anyway, a great website that helped me is
www.pcmech.com/byopc
As far as the actual components go, here is a system that would be great for gaming and around $1200. I'm assuming you already have a monitor, keyboard, speakers, etc. Anyway, here goes:
CPU- AMD Athlon 64 3200+...$255
http://www.newegg.com/app/ViewProductDesc.asp?description=19-103-502&depa=1
RAM- 1 GB Corsair XMS PC3200...$194
http://www.newegg.com/app/ViewProductDesc.asp?description=20-145-450&depa=1
Motherboard- ASUS A8V Deluxe...$129.50
http://www.newegg.com/app/viewProductDesc.asp?description=13-131-510&depa=1
Hard Drive- Western Digital 120 GB...$80
http://www.newegg.com/app/ViewProductDesc.asp?description=22-144-118&depa=1
Video Card- eVGA GeForce 6800GT...$395
http://www.newegg.com/app/ViewProductDesc.asp?description=14-130-208&depa=1
Optical Drive- SONY DVD/CD-RW Combo 52x32x52x16...$38.50
http://www.newegg.com/app/ViewProductDesc.asp?description=27-106-818&depa=1
Case- RAIDMAX gaming case w/ 420 watt power supply...$46
http://secure.newegg.com/app/CustratingReview.asp?DEPA=1&item=11-156-135
Floppy Drive- SONY Floppy Drive...$7
http://www.newegg.com/app/ViewProductDesc.asp?description=21-103-109&depa=0
Operating System- Windows XP Home OEM...$92.25
http://www.newegg.com/app/viewproductdesc.asp?description=37-102-151&DEPA=6
That comes to a grand total of $1237.25 and man, that would be a sweet system. You would be able to run any game out right now on high settings very smoothly. Is building your own something that you would be willing to do?