Depends what you want to observe, and what your budget is, really. You might be better off finding a local astronomy club and popping along for a demo and some advice first.
A newtonian reflector of the type shown in pscocoa's first link is probably the best buy for the beginner. You get a decent amount of both aperture size and magnification for your money, meaning it has decent power to collect light from dim objects and probably enough magnification for a beginner. I bought a 114mm x1000mm job for Mrs. KW a couple of years back, for much less than the Maplin one (which appears to be 200mm, so admittedly a bit more aperture).
Whatever you get will need pretty painstaking setup of the mount to get it aiming where you want to be. Don't be too swayed by electronic mounts with thousands of objects already in the database. You still need to set it up very accurately before it'll point itself at the right bit of sky.
Also.. understand that this won't give you stunning views of the crab nebula and mountains on Mars, etc. Most items just become larger blobs than they are by the naked eye.

The most fun I've had has been examining the surface of the moon, which is quite impressive through a relatively low budget Newtonian reflector.
Oh, and get a decent coat, too.
