Go with this if you can over your 3.
http://www.cyberpowerpc.com/system/Gamer_Infinity_8000_Dream/Gamer Infinity 8000 Dream - $787.
Case: CoolerMaster Elite 310 Mid-Tower Case with See-Thru Side Panel (Blue Color)
Internal USB Extension Module: None
Neon Light Upgrade: None
Extra Case Fan Upgrade:
Maximum 120MM Case Cooling Fans for your selected case [+9]Noise Reduction Technology: None
Power Supply Upgrade:
600 Watts Power Supplies [+26] (XtremeGear SLI/CrossFireX Ready Power Supply)
CPU: (Sckt775)Intel® Core™ 2 Duo
E8500 CPU @ 3.16GHz 1333FSB 6MB L2 Cache 64-bit [+20]Cooling Fan: Asetek LCLC 120 Liquid Cooling System 120MM Radiator & Fan (Extreme Cooling Performance + Extreme Silent at 20dBA)
Motherboard: GigaByte GA-G41MT-ES2L Intel G41 Chipset LGA775 DDR3 mATX Mainboard w/ 5.1 Audio, GbLAN, USB2.0, SATA, 1 Gen2 PCIe, 1 PCIe X1 & 2 PCI
Memory: 4GB (2GBx2) DDR3/1600MHz Dual Channel Memory Module (Corsair or Major Brand)
Freebies: None
Video Card:
NVIDIA GeForce GTS 250 512MB 16X PCI Express [+45] (Major Brand Powered by NVIDIA)
Video Card 2: None
Video Card 3: None
Dedicated PHYSX Card: None
Multiple Video Card Settings: Non-SLI/Non-CrossFireX Mode Supports Multiple Monitors
LCD Monitor: None
2nd Monitor: None
Hard Drive: Single Hard Drive (500GB SATA-II 3.0Gb/s 16MB Cache 7200RPM HDD)
Data Hard Drive: None
Hard Drive Cooling Fan: None
USB Portable Drive: None
Optical Drive:
Sony 20X Double Layer Dual Format DVD+-R/+-RW + CD-R/RW Drive [+2] (BLACK COLOR)
Optical Drive 2: None
Sound: HIGH DEFINITION ON-BOARD 7.1 AUDIO
Speakers: 600Watts PMPO Subwoofer Stereo Speakers
Network: Onboard Gigabit LAN Network
Modem: None
Mega Notebook/Netbook/Server Bundle: None
Keyboard: Xtreme Gear (Black Color) Multimedia/Internet USB Keyboard
Mouse: XtremeGear Optical USB 3 Buttons Gaming Mouse
Gaming Gear: None
Extra Thermal Display: None
Wireless 802.11B/G Network Card: PCI Wireless 802.11g 54Mbps Network Interface Card
External Wireless Network Card: None
Wireless 802.11 B/G/N Access Point: None
Bluetooth: None
Flash Media Reader/Writer: None
Video Camera: None
Headset: None
Printer: None
Printer Cable: None
Power Protection: None
IEEE1394 Card: None
USB Port: Built-in USB 2.0 Ports
Floppy: None
Operating System: Microsoft® Windows® 7 Home Premium (64-bit Edition)
Media Center Remote Control & TV Tuner: None
Office Suite: Free 60 Days Microsoft® Office® 2007 (Words, Excel, Access, Power Point, Outlook + More) - Microsoft Windows OS Required
Going this route is giving you as much CPU, GPU that you can get for under $800. Building it yourself might save $50-$75. But the OS might be x-factor.
YMMV