Gary, I am a one man show but only after my son joined the Army.  Before that, he ran the computers for 6 years.  I can do this by myself, only because my customers have had over 6 years of training on using the viewing stations.  My viewing stations are very simple.  I use ONE computer (Pentium 4 3.02 GHx) running Windows XP Pro.  I have (2) Western Digital 10,000 RPM hardrives, one for the 2 programs I use and the other is for Windows Temp file.  I have a Seagate 750GB hardrive that has the photos on it.  I have 3.5 GB of memory.  Software is Windows XP Pro and Betwin software.  Betwin software allows me to set up 4 viewing stations on one computer with each viewing station acting independently of each other.  I have 4 video cards, 4 mice and 4 monitors hooked to the one computer.  I use the viewer inside of windows for viewing photos.  Since 90% of the world uses windows, I do not have to train them on how to use the computer.  When I transfer my photos from my processing computer to the viewing stations, I use a Gigabyte network and I only have to transfer to 1 computer instead of 4 different computers.  It makes the transfer 4 times faster.  
My processing computer is a Intel i7 2.66Ghz quad core
processor installed on an Asus p6T motherboard using an Nvidia video card w/ 512MB of memory, 12 GB DDR3 memory, 2 Western Digital VelocRaptor 10,000 RPM hard drives (one for programs and one for Temp files), 3 Western Caviar Black 1 TB 7200 RPM hard drives for photos.  I use a Dell Ultra Sharp 2209WA Monitor.  I am using Windows 7RC for operating system, Photo Mechanic for download photos & adding IPTC.  
The key to making this work is to use the fastest computers along with the fastest software with an efficient workflow.  I use the Omniflash UBMA USB compact card reader and Transcend 8 GB 300x compact flash cards.  This downloads my photos faster than 150x 1GB cards on a non UDMA reader.
I build my own computers because nobody makes a computer that fits my needs and I don't need a warranty.  If something brakes down in the field, I need to fix it there on the spot or I am out all the business for that weekend.