Heh... you're all comparing apples to oranges.
http://www.dell.com/content/products/features.aspx/cto_xpsdt_710?c=us&cs=19&l=en&s=dhs
Check the model on the far right...
I'll summarize it for people who don't want to go there and look.
Intel Core 2 Duo E6300
nForce 590 motherboard
WinXP Media Centre 2005
nVidia GeForce 7900 GS (256mb)
1GB of PC5400 (667mhz) (2 x 512mb, dual channel)
250GB S-ATA Hard Drive, 7200RPM
20.1" Widescreen LCD
16x CD/DVD burner
15 months of AntiVirus
MS Works 8
750-watt power supply
1 Year Warranty
$2000 price tag, excluding tax and shipping
Here's a good design for a solid rig-quite a bit less expensive while faster
Intel Core 2 Duo E6600, Retail - $320
ECS PN2 SLI2+ nVidia nForce 680i SLI motherboard - $240
WinXP Media Centre 2005 with Vista upgrade - $110
nVidia GeForce 7900 GS KO - $185
Corsair TWINX 2GB of PC5400 (667mhz) (2 x 1024mb, dual channel) - $240
Western Digital Caviar SE 16, 250GB SATA 300 Hard Drive, 7200RPM, OEM - $85
Sceptre X20WG Naga, 20.1" Widescreen LCD, 5ms refresh, 1000:1 contrast, 1680x1050 resolution - $250
Dual Sony DRU-120C DVD Burners - $40 each, $80 total
Microsoft Office 2003 Basic, OEM or Office 2003 S&T Edition - $170 or $135
Coolmax XC1-600B, 600-watt Power supply, PCI-e SLI ready, sata-ready - $100
Ultra Wizard Black ATX Mid-Tower - $35
$1815 price tag, excluding tax, labour, and shipping
Boosts include a faster processor, next-gen motherboard, twice as much memory, dual DVD burners, and a full office suite. Price without these boosts would decrease rapidly.
Intel C2D E6300 - $191 ($129 saved)
Corsair TWINX 1GB of PC5400 (667mhz) (2 x 512mb, dual channel) - $107 ($133 saved)
Single Sony DRU-120C DVD Burner - $40 ($40 saved)
Total with these three basic items cut back... $1513
True this will be a bit above your budget with full or $200 saved if you scale it a bit down... the places to cut prices are going to NewEgg for a nForce 650 motherboard, a C2D E6300 or E6400 processor, a single DVD burner, a less-expensive office suite, or less RAM.
Put together at TigerDirect; many rebates will apply. Price will be below $1815, closer to $1645 without shipping+tax but with rebates.