...just make sure you get a 5.1 system as a minimum with the subwoofer powered by the Amp, and not an Active one as its easier to control the volume of it.
Sorry to disagree, but I'm not so sure about that, Bat - I think you'll find most people tend to go for a powered "Active" subwoofer, as these contain their own amplifiers, and don't drain all the bass from your main amp. I have a Yamaha SW-320, and the volume is easily controllable.
HERE is an article on subwoofers, which may be of interest.
You will definitely reap the benefits of a decent 5.1 system, and could probably do quite well in the sales at the moment.
THIS looks like the kind of thing you're looking for, but you really need to hear the system before you buy, so you'll have to drag Mrs Clive round some of your local Hi-Fi and Home Cinema retailers!