with 5 grand you can build any computer you want, here are some suggestions:
scratch the FX-60 and get Opteron 180, same performance for less
Yes the 1900XTX with the crossfire master card is the king right now, but the mobo for them are not quite as supportive (the Xpress200 chipsets getting replaced by xpress300 in june) so if you want absolute best performance you wanna either wait for new mobo OR buy one right now and the get a another one later.
DFI LANParty UT RDX200 CF-DR or Asus A8R-MVP for right now
While I talk about waiting, in june the M2's are coming out too with a theoritical 65% increase in performance. Plus the M2 can use DDR2
OCZ DDR600 1xgb
http://www.newegg.com/Product/Product.asp?Item=N82E16820227217
HDD: 2x raptors or 2x sataII in raid 0
PSU: Antec TruePower 600W with dual GPU support, or any other good brand: Enermax, FSP, Coolermaster, etc..
YOu can consider modular PSU too to remove cable mess
THis is the meat of the system, the rest are up to you.
CAse's should look good to you, sturdy, and have good airflow
FAns: ultra-quite ones, 120 mm preferred
CPU HSF: if you oC, Xp-120 or SI-120 with panaflo 30dba 120mm fan (forgot the part number, but monarch has them for $23 each) OR water cooling solution
Opticals and floppy: doesn't mater the brand, as long as they do what you need them to do
Oh, monitors: Dells are popular, but ask somebody else for other suggestion
5 grand will do for this thing, but you can probably get the same performance for a lot less.....