It was interesting to see Bev Bright's texture lecture at Develop in Brighton, and how different channels in photoshop are used as light maps, or reflection maps for each texture, etc. Although not a techy developer, so a lot of it went over my head, I walked away with the feeling that the size of textures used, was due to the demands on "through-put" rather than storage. However, I could well be confusing this with bump mapping, which they have removed from PGR4 because it was so minute, you couldn't notice it in PGR3, making it a waste of time, and resources, so perhaps that's what freed up "through-put", and storage for textures is another matter altogether.

On older formats we have seen epic games split over multiple discs. I guess in this case, it made more sense to be efficient with textures and cram them into one disc, than to be bloated, and make it multi-disc.

It's certainly interesting to chart the differences in X360 and PS3 as they become apparent.
I wonder how long it'll be before a super elite X360 comes along with built in HD-DVD, or, if BluRay becomes standard, even a BluRay drive. =P ^_^ That'll be funny.

You don't want to do everything with dynamic lighting because then you'd have to simulate a light in every window you want to be lit, plus every neon sign, plus every light on a street sign, plus every streetlight. I don't think there are any computers that can do that lot in realtime at 1080p@60Hz.

So what game devs do is create different textures for day/night environments that fake most of the above light effects. With PGR's high resolution textures that all adds up to a huge amount of data. So much that it won't fit on a DVD apparently.