Hello AnthonyB
I see from your profile a UK web address, if you are indeed in the UK try www.bck.co.uk (Look under accessories) and you will find a couple of systems designed for playing keyboards in the home.
If you want a more professional speaker system have a look at the SR speaker systems distributed by Big Cat Audio www.srtechnology.co.uk which should suit your requirements. (The Club series would probably suit you best)
At the UK Keyboard Festivals most of the Keyboard manufactures use SR speaker systems for demonstration purposes.
Hope this helps

Bill