Before you shell out you need to think what you are going to use it for.
Cheap TFTs are fine for simple Word Processing etc but if you wish to view games and videos etc then you need to look into them in more detail as they tend to smear.
Check the pixel pitch and the response time ( 15-25msec good for games etc, 35msec is tolerable - above 45 not good). Msec not nanosec (nsec) - if you can get one at 15nsec it would probably cost around £1m.
Also check the viewing zone and try to get one with around 150degrees horizontal and vertical.
I use a iiyama 4821 which is excellent but expensive at £700 rrp (£650 at DABS) which is excellent on games etc. I bought my kids a Packard Bell 15inch LCD but they switched back to a 5 year old 17inch Sony CRT.
Check the PC Pro Web site which has good reviews on equipment, you will probably have to register but it is free and worth it
http://www.pcpro.co.uk/ . They have something called an "A" list and a number of group tests on-line.
PC Pro have just placed the Iiyama ProLite E431S in the "A" list which though restricted on viewing (140degrees H 120degrees vertical) has an excellent refresh rate of 15ms (mine has 25msec and the games are excellent). Price at DABS without speakers £320.
iiyama also provide 3 years on-site warranty with the screen
Really, do your research and do not skimp for a few quid, you will only regret it later and have to upgrade earlier...
Also remember that you will pay upto 10-25% more at PC World than internet suppliers such as DABS or Microwarehouse (
http://www.microwarehouse.co.uk ) and have less availability with you ending up accepting the compromise...