This soundtrack is amazing. AMAZING. Forget about 'Moon Safari', forget about the film, forget about life and just enjoy. I didn't know much of Air before I heard this(besides 'Sexy Boy', which I thought was a nice idea but ultimately a bit too cheesy). Anyway this soundtrack makes me want to buy everything they've ever produced, despite what assorted 'Moon Safari' fans say here about it being far from their best work.
I have one criticism of this soundtrack, which is that some of the tracks are way too short. Air could have made a 60 minute extravaganza here without a lot of effort and a 74 minute masterpiece with a bit of extra work, that's how good the tracks are. As it is, you get 40 minutes of exceptional work - And a work is what it is, this is no french pop album...It reminds me of Pink Floyd in quite a few places, with hints of ambient Aphex Twin and Godspeed You Black Emperor. So think excessively ambient prog rock, with sprinklings of electronica and a generally dark theme throughout.
Basically if you like music, you need this album. It's a great chill-out album, but don't expect it to be just that - the drumming on some of the tracks is fantastic and the epic quality of the whole album just pervades the room you play it in, demanding attention. It's dreamy but gothic, progressive but never over-ambitious, always sublime and if you like the film...so much more than just a soundtrack. You'll know what I mean if you get to hear it.