No holds barred here.  This would be a killer machine capable of just about anything and take advantage of two CPUs to boot.  Only difference between this and the SCSI Dream Machine is the motherboard and CPUs.

• CPU:  TWO Intel Pentium 3 E 850 MHz CPUs
  OR:
  If on a budget, get TWO Intel Celeron II 566 CPUs and run them at 876 MHz (103 bus speed).
• Motherboard:  Tyan Tiger 100 Dual (Model S1832DL). 
• RAM:  Four Corsair / Micron 128 MB PC133 SDRAM DIMMs for a total of 512 MB (if using Asus P2B-F or Abit BX6 Rev. 2).
• Hard Drive:  Quantum Atlas 10k 18 GB 10,000 rpm Ultra2 SCSI Hard Drive with 2 MB cache buffer (2 or 3 would be nice - 3 in a RAID configuration)
  OR:
  IBM 18ZX 10,000 rpm 18 GB Ultra2 SCSI Hard Drive with 4 MB cache. 
• Video Card:
  Matrox G400 MAX video card with 32 MB of RAM and two of the monitors listed below. 
  OR
  Hercules 3D Prophet II GTS (GeForce II) card with 64 MB DDR RAM and Video out. 
• Case:  SuperMicro SC750-A Server Tower Case with 400 watt PC Power & Cooling power supply.
• Modem:  3Com/US Robotics External FaxModem Pro (USB/Serial). 
• Monitor:  22" Mitsubishi Diamond Pro 2040U monitor with .24 dpi Trinitron tube (very expensive).  (or 19" Sony GDM-F400 - expensive).   
• CD-ROM Drive:  Plextor UltraPlex Max 40x Narrow SCSI CD-ROM Drive
  AND:
  DVD-ROM Drive:  Pioneer 6x SCSI DVD-ROM Drive with software decoding (purchase the RealMagic Hollywood Plus decoder card if desired)
• Sound Card:  Xitel Storm Platinum Gamers Pack with "Force Feedback" headphones - A PCI Vortex2 3D audio sound card.
  OR:
  Creative Labs' Sound Blaster Live! Platinum
• Speakers:  Altec-Lansing ADA-880 Quad speaker setup.
  OR:
  Klipsch ProMedia v.2-400 Quad speaker setup - 400 Watts!
• Backup:  Iomega SCSI Internal Zip Drive
  AND Castlewood Orb 2.2GB SCSI Internal Drive.
• Floppy Drive:  Teac 1.44.
• Mouse:  Microsoft IntelliMouse Explorer USB or PS/2.
• Keyboard:  Microsoft Natural Keyboard Pro USB or PS/2. 
• Printer:  Epson Stylus Color 900 (inexpensive)
  OR:
  Hewlett Packard 2000CXI Thermal Inkjet (expensive)
  OR:
  Tektronix Phaser 360 Wax-Based Printer (very expensive).

 Options:

• Game Controller:  Gravis Xterminator Game Pad.
  OR:  MS SideWinder Freestyle Pro USB GamePad (gyroscope)
  AND:  MS SidWinder Force Feedback Pro Joystick. 
• CD-ROM Burner:  SCSI Plextor 12x write, 4x rewrite, 32x read Internal
• Scanner:  HP 6200C Scanner.
• Digital Camera:  Kodak DC290.
• Video Capture:  A Targa card (I won't get into this one). 
• UPS:  OptiUPS 650ES Battery Backup with Voltage Regulation
  OR:
  APS Smart-UPS 700Net Battery Backup (more expensive).