I'm not familiar with prices in the UK, but I would personally take the chance to go for an LCD screen. About the only drawback these days is for those who need accurate colour reproduction. For general email, internet and games, LCDs have pretty much caught up. Not to mention they also use less power and generate less heat in the room too.
I have a Dell 1905FP that is working great and is a pretty decent size. Remember with LCDs, you get the full size stated. So 19" is actually 19", not 18" like on a CRT. It costs about $550CDN, but I got it on sale for $400CDN.
If your PC has a DVI port on the video card, try to get a LCD with DVI as well as the quality is a little better.
goates