KVM switches have their drawbacks, too: they are expensive, they limit you to a set number of ports (2/4), most/all of them don't support absolutely all possible keyboard and mouse functions, they don't allow you to switch anything besides the KVM (one each of K&M), and most/all of them will hurt your video resolution to some degree. The latter may not seem to be an issue, as a good active circuitry KVM will quote a resolution of something like 1600X1200, but this might be at a limited refresh rate (typically 75 Hz), and in any case, 16X12 is going to be limiting for more and more people as video cards get more powerful (e.g., your Geforce 6 is going to be doing full antialiasing at a resolution of 20X15) and larger monitors become more commonplace. Passive video switchboxes, like the $14 model mentioned above, are pretty crappy, even at a resolution around 10X7.
My personal solution is to use A) a multi-port passive USB switchbox (these cost $20 for a 4-port model from a number of vendors) and B) a pair of monitors (19" in my case) that can be connected to a 6' shielded/high-resolution VGA extension cable that comes out of each of 4 computers. In other words, to switch between computers, I press the button on the USB switchbox (connected to a USB hub, which my input peripherals connect to) and then hook up the VGA extension cable (from the computer) to the applicable monitor's VGA cable.
The advantages of this setup include the following:
A) no limit on the number of computers or monitors I want to use; if I wanted to switch between 12 computers for some oddball reason, I could buy a couple more USB switchboxes
B) ability to direct a computer's output to my "main" or "secondary" monitor at will (one example: I can download a large file on one computer, then move its display to my secondary monitor while I begin a computer game on the main monitor using a separate computer)
C) ability to set up a "dual-view" setup so that the 2 monitors function as a larger single-screen
D) ability to switch multiple input peripherals, including joysticks, cameras, etc., even including multiple peripherals of the same type (e.g., I have a cordless Logitech optical mouse for web browsing while leaning back in my chair, and a corded Microsoft Intellimouse that I use for gaming)
E) low-cost
F) no need to limit the use of "elite" input peripherals for gaming; I don't have to worry about (for example) running a program like "PS2rate" that changes the polling rate of the PS2 port, and I don't have to worry about whether a mousewheel or 4th and 5th button will be supported by the KVM
G) no limit on the video resolution, at least that I can detect at a resolution at 1600X1200, and no limit on the refresh rate
H) ability to switch printers without worrying about networking them
I) I don't do this, but you could even switch your audio by using a USB audio card
I could go on, but you get the idea. The drawback is that it looks and feels less elegant than simply pressing a master button on a KVM switch, and it does take a few seconds to plug in/out the monitor's VGA cable to the VGA extension cables coming from the computers. If I was a system administrator switching between computers multiple times per hour, all day long, every day, I'd probably pay the bucks for a conventional KVM switch.
Hope that helps some other frugal Anandtecher. 🙂
Btw, they do make KVM switches that use USB connections, but they are expensive, they have the video resolution limitations discussed above, and they don't allow for the flexibilty of multiple monitors.
[Edit: Caution! Evil 666th post.]