I am going to agree with everyone and say - all of the big brands - Gateway, Dell, Compaq/HP, ect, are shoddily built and overpriced. Stay away from them. If you don't have the skills to build your own machine, then find a local business, and have them get build it for you. I reccomend comparing the prices of the parts they sell you with
www.newegg.com - they are probably the best online computer parts retailer, and make sure they don't sell you parts for way more than they are worth.
Checking on
www.newegg.com, you could get a complete system with the following for a total of $1599.
Athlon64 3000- $223
Right now Athlon64s are the best for gaming - the 3400 model cost ~$410, but is as fast in most cases as $800 Pentium4 Extreme Editions. The 3000 model will still have very good performance, in many cases matching 3.2Ghz Pentium4 when it comes to games.
1Gig Corsair PC3200 DDR-SDRAM - $164
Stick to Corsair or Crucial RAM, best brands out there.
Motherboard with built-in sound/LAN - $95
The audio should be good enough, might want to get a sound card later if you don't like it.
Sapphire Radeon 9800 Pro 128Meg video card - $210
Right now, Ati's cards are dramatically outperforming Nvidia's at new games; the GeforceFX series just can't do DX9 very well. Just STAY away from any card made by Powercolor.
DVD burner + DVD ROM drive - $91.50, $30.
LiteOn and Plexor are good brands here.
120GB SATA Hard Drive - $105.50
I would stick with Western Digital or Seagate brand drives.
Antec Case with 400 Watt Power Supply - $92
Make sure you get a a good powersupply - Antec and Thermaltake are brands that have a good reputation.
19" PerfectFlat Viewsonic CRT monitor - $214
Monitors are more personal things, you definatly want to check these out in person.
Logitech z-680 5.1 channel speakers -$279
I have a friend with these, they work very nicely; but speakers again are a matter of prefernce; Altec Lansing and Klipsch also build very good speakers as well.
WindowsXP Home Edition - $95
You need Windows if you want to play most games; most people don't need the more expensive Pro edition; only get the Pro edition if you need the extra networking features or if you end up getting a dual-processor machine, other wise Home and Pro are identical.