Most brands are 'good' these days, not much difference. Many brands even use the very same hardware anyways. It mostly depends on the budget you want to spend.
Important points for LCD screens are:
1) The refresh speed/delay, the lower the better. You should have an absolute maximum of 5ms, anything higher is absolute shit. Preferable something like 2ms to 3ms.
2) The contrast ratio. I would say at least 3000:1.
3) The dead pixel policy. Almost every brand will _not_ replace the screen if there are only a limited number of dead pixels. Read the fine print in the manual _before_ you pay for the screen! This is very important. For example, you could have like 10 dead pixels, yet all across the screen. This is different than having 10 dead pixels in one quarter of the screen. The later might mean they will replace the screen, the first will not. So, read the policy carefully. To read this, you probably must open the box and read the manual. Ask to do this in the store, don't let you tell you otherwise. They must allow it.
4) Very important for ergonomics: check if the screen can be tilted and can be lifted higher or lower. Not all screens can be tilted, and even less screens can be lifted higher or lower.
5) The ability to show different resolutions without distorting/stretching the image across the screen. This can be important if you plan to hook up your laptop to the screen for example.
eg: the older widescreen Samsung SyncMaster 206BW is an excellent screen and can show different resolutions, but they will all be stretched across the screen. This is of course not very good if you hook up a 4:3 laptop.
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And above all, ask to hook up the screen which you wanna buy (not a demo model, but the exact screen!) so you can check for dead pixels in the store and can see the screen in 'action'. This is very acceptable for TVs, yet often people forget that it is equaly important (if not more important) for computer screens.
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