I work next to both Best Buys and Frys Electronics here in Phoenix. I have found that Frys has the best prices and selection of HD movies for both HD-DVD & Blu-ray titles. I highly recomend Frys over BB for HD movies !
I used to go to Best Buy nearly every week to get a new SD-DVD new release that I wanted.
I haven't shopped there regularly for nearly a year now that I have switched over to Hi-Def media. The fry's near me consistanly beats them in selection and price for 95% of all the Hi-Def discs.
The only time I set foot in Best Buy anymore is when they have something that I can't find at fry's, like the recently released Ocean's 11 Three Pack on HD-DVD.