NAD is a very good make, you may also consider the likes of Marantz, Arcam, and Denon. Sony also gives very good quality products for cheaper prices, but they concentrate more on their multi channel amplifier range than stereo amplifiers.
Have a peek at some of the stuff on www.avland.co.uk
This is a very nice amp for a little less money...
Actually, thinking about it, you should consider buying a multichannel amplifier, you can run it as a stereo amp, but can upgrade it at a later date. It gives you the benefit of the newer technologies as high quality audio companies are turning their creative efforts towards the sound that surrounds