This is by far, the one piece of software I can not live without on OSX! $40 is such a small price tag when I realize how much I absolutely rely on it. I can barely function on a Mac without it (and LaunchBar).
It can be a bit involved setting it up, but man, once you do, it's pretty seamless. And there are more than enough options to customize it to your exact liking/use.
Want the pager nice and small? Want it to autohide? Do you want to switch desktops by mousing to the screen edge? Want to only switch if holding a key? No problem at all. Want notification, or how about a menu item? Little pager icons, or no icons? Want a different look, make or download a skin.
I have mine set to 15 desktops, with particular apps assigned to the various desktops. For example, I can keep Safari, iCal and Mail open all the time, each in their own desktops, full screen, and never once have to hide or minimize any of the windows.
I have eight Terminal windows open, with four windows in one desktop, and four more in another desktop... I ssh to a lot of machines. This is done by duplicating Terminal.app, and setting up a startup script that opens the four windows when Terminal is launched.
I pretty much never have to deal with moving windows around or minimizing windows to the dock to get to the one I want, because they're all there on their own desktops!
Some of my desktops don't have anything in particular assigned to them and I use those for working in the Finder or other apps that I occasionally open... like scratch space. Got a bunch of windows open on your current desktop and need a fresh one? No need to minimize or hide all, just move to an open desktop!
When you use the dock or apple+tab to switch between apps, your desktop changes accordingly, so you don't even need to use the mouse to switch anywhere.
When you launch an app via LB, QS, or POF (plain 'ol Finder), if that app is assigned to a desktop, that's where it will always be whenever launched, every time.
Got multiple monitors? No problem! You can even remove the monitor while it's running and it just resizes and keeps on going like a good little app should.
Not only does it do just about anything you want it to do, it does it FAST and efficiently. I'm on a 2000 Pismo, 500Mhz, which is no speed demon, and have no problems at all -- switching is extremely fast with no lag. The only time switching may be a little odd, is when an app is not responding or really really busy doing something. CPU usage is also very minimal, which on the Pismo is always a concern of mine.
I really can't say enough about this product. There are a few other virtual desktop apps out there, but none are as full featured or rock solid as Codetek Virtual Desktop. Seriously.
ps. and no, they didn't pay me to write any of this