Edited to reflect currenlty available titles.
Borders have many Blu-ray titles available at thier Oxford Street store for £4.99. Look for the titles priced at £15.99 - most of these will ring up on the till at £9.99 before the 50% closing down sale discounts. The titles are mainly Warner Brother's Titles
Troy - Director's Cut
The Last Samurai
Interview with a Vampire
Harry Potter (not too sure which movies)
They did have X-Men Trilogy for £17.49 after dicount but have run out of these but they did get some more in a few days ago so watch out.
These offers and others may be available in the othe branches which are closing down in Blanchardstown, Llantrisant, London Colney and Swindon