Geeks' Dream . . . (plz help me make it true)

No I am not begging for help with money or anything of the sort just help with picking the parts for this soon to be reality machine.

APPROXIMATE PURCHASE DATE: Next 2-3 months (just trying to plan and get as many ideas as possible)

BUDGET RANGE: Try to keep it under $20,000 (yes I did type twenty-thousand dollars)

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Legal network penetration testing, rainbow table creation, video/audio editing/encoding, security testing, Several Virutal Machines when penetration testing, programming, gaming. Oh yeah and don't forget about sever multi-tasking.

PARTS NOT REQUIRED:

PREFERRED WEBSITE(S) FOR PARTS: newegg.com, but will buy from any reliable site

PARTS PREFERENCES: nvidia graphic cards (2 or 3 of them)
slight preference for AMD CPU but will go with whatever has best proformace
Water cooling

OVERCLOCKING: Maybe (wouldn't want to get greedy and break it)
SLI OR CROSSFIRE: Yes
MONITOR RESOLUTION: 1920x1080, 1920x1200 (and several of them)

ADDITIONAL COMMENTS: Ok, if you haven't figured it out I will be buying probable the best computer I can come up with. That being said this is not strictly a gaming PC since I don't game too much =P This is the computer will be doing anything and everything.

Thanks in advance for all of your great ideas.