The Book People have some ridiculously good deals on Who-related books at the moment. I think some of these have been up before, but to summarise:
Doctor Who Encyclopedia - £5.99 (£11 off)
Doctor Who Storybook 2007 - £1.00 (£6.99 off)
Doctor Who: The Official Annual 2007 - £1.00 (£5.99 off)
Doctor Who: Time Travels - £7.99 (£10 off)
Doctor Who Quiz Book Collection (3 Books) - £3.99 (£10.98 off)
Dr Who Activity Set (4 Books) - £4.99 (£11.97 off)
Note - The Quiz / Activity books were rather overpriced to begin with, and those two bundles have two of the same books in them.