I've been using LCD panels for a little over a year now. Between home and my day job, I've used a variety of panels.

The key to using an LCD is having it calibrated. Where an uncalibrated CRT can be somewhere in the ballpark, most LCDs are not. Calibration is a necessity.

Once calibrated, I've been very pleased with them. They have a higher contrast ratio than you can get out of prints, and generally show more detail in the shadows, so you do have to keep that in mind.

Cheap units are generally more difficult to calibrate, lose their calibration more quickly, vary their color more with changes in brightness, and have more variation across the screen. That doesn't mean that you need to break the bank, I've actually been pretty pleased on the cheap end with Viewsonic VP920b units. I think they're only about $240 (maybe less), but aren't bad at all, once calibrated. They do have a very narrow vertical viewing angle.

The biggest thing to watch out for are that you want a model with 8-bit color (some use 6-bit with dithering), and if you have a DVI output on your video card, get a model with a DVI input. It's much sharper than RGB. So much so that you'll wonder how you ever got along with a CRT.