Well, if peripherals are part of the equation, it becomes easier:
Computer: Any fast PIV w/875, SATA etc
Case: custom built hardwood silent enclosure. Hire a master cabinetmaker to construct it to fit standard ATX components. Custom CNC machined huge heatsinks milled to fit the enclosure allow low speed baffled airflow from 1 huge fan at the back to effectively cool entire system.
Primary display: 19"-21" 16ms response LCD 1600x1200 (if one exists)
Secondary Display: HDTV Capable LCD DLP Projector with 12' screen
Sound Card 1: Audigy 2 for games and movies
"Sound Card" 2: MOTU 8 channel 24/192 firewire interface x2
Speakers: 4 Mackie HR 8/24 powered monitors, front and rear, with matching 6/24 centre channel and subwoofer.
If I could justify a mic as part of the 25K, that would cover the balance.
And if I could throw in
Herman Miller Chair, then I would be truly a happy nerd.