I bought this Blu-ray to watch on a friend's machine and I was so impressed with the quality gain that the very next day I replaced my computer with a new system that can handle Blu-Rays. Yes, the quality difference was THAT CONVINCING. Instant assimilation!
I think pretty much all of the additional material is in standard definition. This includes the original trailer, and you can clearly see the difference in quality. The trailer, despite only being 14 years old, has grain and jitter, but by comparison the HD presentation of the movie is crisp, detailed, and vivid. The sound is truly excellent.
If you ever got a thrill from watching the fleet's desperate defence of Earth, or seeing the vein pop out of the side of Patrick's head when he goes off the deep end with his Ahab impression, you absolutely must buy this Blu-ray. And a player to watch it on... I don't call mine my Blu-ray drive, I call it my First Contact drive :)