Try Casino Royale (from someone who was a anti next gen HD person). I tried it and at first I saw the night scenes and I thought to myself, "Ok, the picture is slightly better than a normal dvd, a bit more sharper etc", but then when I moved to a day scene, I litterly wet myself, I was just gob smaked, the picture was sooooooooooo "detailed" and pin sharp, there was no comparison with a normal dvd and this was viewed on a 30" LCD at 720p (so still not seeing the FULL Blue-Ray quality at 1080p).
I played Gladiator on SD-DVD that I had and i do have to say the picture was alright but a little dissapointing, hopefully Sony will allow the PS3 to upconvert normal DVD's in the future with a firmware update as xbox 360 does it.
It should be noted that the same Gladiator DVD look amazing on a £20 crap DVD player on a normal TV that I had (non-LCD), so I think this may be an LCD issue, as playing PS2 games also produced in not too good PQ on a LCD.