The only Blu-rays I've bought in store were from Zavvi just before it closed. Morrisons also sometimes have Blu-rays for under a tenner (never anything I want to watch, though!).
I agree that the HMV in-store prices are ridiculous. I bought a DVD there a few weeks ago, and was asked if I would like to sign up for their loyalty card - 'free, is it?' I asked - and was astonished when told 'sorry, no it's not'! It may be only £3, but Nectar and Tesco don't charge, neither do Game, who have a better selection of, er, games.
So far as Lovefilm is concerned, they do have the latest releases, but you may need to join the queue. I'm trying to rent the Star Trek original series Blu-rays, to see if they're worth buying, but they should on my rental list as 'long wait' ...
PS3 / 360 / Pioneer BDP-51FD / Sony L40-W4500 / Panansonic DMR-E95H / Onkyo 706 / Kef Reference One fronts / Kef Ref 100 centre / Kef HTS2001.3 surround back x 2 / Polk LS f/x bipole rears x2 / Velodyne VA-1215X sub / Stands Unique rack / Argos TV stand