We all use iBook laptops in the company I work at, no desktops. Someone pointed out that UK health and safety laws require that we provide something more suitable for desk work (fair enough, don't want to cripple the staff), so we've just brought one of these to test out.
http://www.johnlewis.com/Computing/...ds/Computer+Stands/411/230306174/Product.aspx
It's not very beautiful, and it's not very mac-like, but it does the job of bringing the screen up to eye-level.
A massive pro is the 4 port USB hub on the back - it gives somewhere permanent to plug in the USB flash drive, the mouse, external keyboard, printer and other junk. It's a powered hub with a mains lead, but I found it can also be used unpowered (mouse keyboard etc still work, tho the instructions don't mention this possiblity).
Pretty adjustable too, with different levels of height possible. Gives easy access to front and side optical drives. (there's a retainer on the front that hinges down.)
Cons - expensive, big, nowhere to slot the external keyboard when not in use (unlike say, the Griffin iCurve, which has its own issues)
Some of the staff love it anyway, and it works with MBPs too, so we'll probably buy a few more.