If you want a quality KVM switch, you're going to spend $100 to $150. With that said:
Avocent looks like a solid chioice.
I have a little Belkin 2-port OmniCube, and it barely gets the job done.
I constantly wish I had at least three ports.
Plus, my crappy KVM doesn't support USB, and since I use a usb mouse, I need one for each computer on my desk which is what the switch is supposed to prevent.
Really I can only use the Belkin to switch the monitor, and that's great because I don't have to crawl around in the back swapping cables or have two monitors on my desk each time I need to do work on another machine, but it is not living up to the potential of the KVM.
My third computer is rarely used because I would need another whole monitor/kb/mouse setup to use it.
The point is, if I were buying a new KVM the Avocent brand recommended above looks reliable.
I would go with a 4-port USB KVM, model
#SV1400UP-AM
Sparco.com is selling that model for
$112.55 as of this posting.
Also,
Price Grabber is a good place to compare prices.
You can hook up 4 usb devices, 4 ps2 mice, 4 ps2 kb, and 4 vga adapters (basically 4 separate computers) to one set of input devices.
That means one USB mouse, ps2 KB, and monitor will control all Four computers.
Avocent also sells a
similar model that is the same except for the addition of audio connectors for each port, but it doesnt' support 5.1 audio.