I just built the below rig and i am thoroughly enjoying the speed of performing any task with the most intense video & editing programs available. Sony Vegas, Cyberlink Powerdirector, CS5 extended, PSP X4, etc.
Im not into playing games so the 16GB of Ram & the single Nvidia 560ti video card is more then sufficient for rendering & authoring most any software programs that photographers like us need.
I highly suggest building your own PC and not buying the ready made brand names that utilize cheap parts or worse yet proprietary parts like Dell ! If you cant build it yourself which really is easy, at least order one from IBuypower and ask them to install the OS for you along with all the current drivers.
Ordered my Parts from Newegg & a few from Amazon:
Case: CM Storm Enforcer Midtower/ USB3.0
CPU : i7-2600K
Mobo: Intel DZ68BC Extreme
Ram : Corsair Vengeance pc1600/ 16gb
Video: EVGA Nvidia 560ti
HDD: SSD 120GB Intel 520 series & 1.5 TB WD Caviar Black
Pwr.Supply: Rosewill Capstone 650watt Gold Rated 80+
CPU Cooler: CM Hyper 212 EVO
Fans: 200mm front intake, 200mm top exhaust, 120mm rear exhaust
NZXT Sentry Mesh 5.25 Bay Fan controller
ASUS DVD Burner
LG Bluray Burner/Player
AFT USB 3.0 Multi-Card reader 5.25 Bay
OS: Windows 7 64 bit
Asus VW246H Monitor/ HDMI
I spent less on this rig then i did for my Canon 70-200 MKII last year !
Regards & Good Luck, Ron