Memoirs of a Geisha. Beautiful, beautiful movie. But why did they use Chinese actresses who don't speak English very well, to play Japanese geishas? 

A lot of Kim Ki-Duk's movies look very pretty, for instance "Spring, Summer, Fall, Winter... and Spring" and "The Bow"

And I was really impressed with American Gangster. Not only the visuals, but the entire movie.

I would like to suggest Aragami (dir. by Ryuhei Kitamura).  The set is quite pretty (the entire movie is set inside an old temple).  What really makes it are the swordfights.  Some excellent stuff, and as I pointed out to my Dad, "This is your (plasma) TV's forte.  Dark scenes and fast movement."  I especially like the final fight which (I don't think this gives away too much) is done in darkness.  Sounds stupid, but you see the fight when their swords clash (producing sparks).  Amazing, gorgeous stuff.  Dark, with a slower pace for the non-action scenes.

The trailer for The Fall, directed by Tarsem. looks to be a visual feast if any indication of the film itself.

I'm surprised Amélie hasn't been mentioned yet. It's a very pretty film. I know it doesn't have an HD release yet (at least not in NA) but the OP didn't mention anything about HD exclusive movies.

KM

I reaaally enjoyed the visuals in I am Legend.
The movie looks so crisp, that it really stands out, you KNOW you are watching a Hi-Def release.
The same goes for 30 days of Night and No Country for Old Men (which I believe was shot with Hi-Def cameras and it shows!).

Finally most of the animated films look awesome and have that "3d effect" we all love from hi-def

I watched Stash 20 (see official site) with my girlfriend last night, and despite the poor image the TV setup reproduces, we were both very impressed with The Tale of How by the Blackheart Gang.  It looked amazing!  A great deal of work has gone into it, and produced a depth rare in most video.

To get an indication, you can check out the YouTube vid below, or have a look around The Black Heart Gang's website, which has some behind-the-scenes stuff.

Quoting Astrakan:

Quote:
I'm surprised Amélie hasn't been mentioned yet. It's a very pretty film. I know it doesn't have an HD release yet (at least not in NA) but the OP didn't mention anything about HD exclusive movies.

KM

I just rewatched that last night! I was going to mention it just now, but you beat me to it.  It is a beautiful film, visually and story-wise.  And Audrey Tautou is pretty easy on the eyes as well. 

"The 6th Day" on Blu Ray has excellent picture. It can really hold it's own against new movies.