Why no SLI or Crossfire? For gaming at $1600, you can get a pretty fast rig. But without the option for SLI or Crossfire, some of your budget has to be unnecessarily diverted to other components that will have minimal or no impact on gaming performance? You could get a gtx 480 or a radeon 5970, but a pair of 470's is faster than both and very much within your budget. So what's the purpose of having a no sli policy on a gaming rig?
Since your purchase date is late november/early december, your build will probably change once AMD's new GPUs come out.
CPU: Intel Core i7 950 ($300)
MOBO: ASUS Sabertooth X58 ($200)
RAM: G.SKILL PI Series 6 GB (3 x 2GB), 1600 MHz, CAS 7, 1.5 V ($155)
GPU: In order of speed: 2 x GTX 470 ($520 for superclocked gigabyte ones) > HD 5970 ($550 for the HIS) > gtx 480 ($429 for the MSI)
HDD: Samsung Spinpoint F3 1 TB ($70)
CASE: HAF 922 ($90)
PSU: Corsair 950 TX ($120)MONITOR
: Samsung LED ($170)
TOTAL: $1625 with the pair of 470's, -$90 with a single gtx 480, +30 with a 5970
prices from newegg. And yeah, the processor heatsink will have thermal compound pre-applied.