I know it's very limited by location, but may be in some other stores if they are clearing stock.
In Wolverhampton Asda, they have a display by the entertainment section chock full of DVD, and games all unboxed but very cheap.
They have quite a few Xbox 360, PS3 and Wii games, and DVDs, but best value were the DVD box sets.
I have bought Heroes season 1 and 2 on bluray for £4 each.
They also have loads of 24, House, Spooks and prison break for similar prices on DVD.
It's like a jumble sale, you really need to have a sort through, but there are some bargains to be had.