Not a luxury any more
I've fitted TV's in two bathrooms. In both I've paid about £400 for 19" screens. (e.g. http://www.ebstore.co.uk/iglu-home/index.html). The picture quality on the pricey ones is not really any better.
I love having it so I can watch the headlines while I'm having a, er...., brushing my teeth.
Dead easy to fit if you're replacing your bathroom, but I wouldn't recommend it otherwise - had rather messy job with an angle grinder to set it flush in a wall in my last place!
Handy tip - extend all the cables to adjacent room/loft space - makes it easier to plug in a laptop/DVD player/whatever.