I don't have a giant TV, but I do have a 24 and 26 inch monitor for our computers.
Our HTPC(hooked up to a monitor until we get said big screen, lol) has blu ray and let me tell you, huge difference.
Biggest show for that, in my opinion, is cars. Looks amazing on blu ray, upscaling looks ok, thats how we watch it normally, but we got the kid the blu ray for his birthday and wow!
The ps3 and the 360, I think, are also great to check out 1080p. Most movies don't play in it, yet, I haven't seen any that go beyond 720, myself, but the game systems can give true 1080 and wow, very clean, bright, vivid details.