I have had a Panasonic plasma and V+ setup for the last 8 months and can recommend it.
Most channels, like the BBC, ITV etc are as near to HD as you could get, Dr Who for example was amazing!
Some channels though are crap and pixelated, Challenge for example, and the upscaling doesn't make any difference - in fact it highlights the fact that the picture is crap!
Just ignore the crap channels!