Using an LCD monitor without Cleartype is like using... um... something worse. It's good.
Especially as it turns out that some of the monitors at work are BGR (the teeny little sub-pixels are usually aligned Red, Green, Blue).
For the naysayers: If you tried Cleartype before but it looked like jagged splinters of colour were trying to jump from the letters, try this - you might find it makes all the difference.
Anyway, because You Know It's Not Been Linked Enough Yet, I present for your viewing ergonomics pleasure:
The Online Cleartype Tuner.
I am for ClearType in theory, but in practice I find it makes the LCD text look blurry.
The only place I like it is on high-DPI displays, eg, those crazy 1600x1200 15" laptop panels. On a 21" 1600x1200, I don't care for it-- the RGB effects around the letters are too visible to me.
I find - weirdly - that not having my contact lenses in makes me more sensitive to the coloury edges. When my eyesight is fixed, they recede and disappear.
You don't by any chance have a BGR 21" do you? The reason I picked up on the difference here was because I could see the colours really vividly on one of the other PCs.
The tuner worked wonders on my lappie's 17" @ 1920x1200; on my 20" flatpanel @ 1600x1200 the difference was negligable. I actually turn Cleartype *on* on my high res CRT (19" @ 1600x1200), it makes a pretty noticeable difference somehow, on other low-res CRT's it's much better to leave it off.
There's also the PowerToy if you don't want to go to the website and/or not an Administrator. That's always one of the things I install on almost all computers along with a host of the other PowerToys.