Check out the deals on Virgins website. They have some good deals for new customers and you can haggle to a certain extent.
I recently got an upgrade from my HD box to a TiVo box(much better than Sky box) and got to keep my HD box installed in another room for free. Broadband upgraded from 20mb to 60mb. Free Superhub 2, free calls to my Virgin mobile from my homephone. And all for the same price I was paying before, and I haggled for free installation and saved £49.99, and the engineer turned up within the 2 hour timeslot and set everything up including the Superhub.