I love the artistry of pre-rendered backgrounds (I even made a
thread a while back about that fondness), but aside from one advantage, today's rendering technology makes real-time backdrops look just as good if locked with a static camera angle. The only give-away is aliasing. That's what makes pre-rendered backgrounds still appealing to me. No jagged edges. Great (if ephemeral) image quality that can only be matched in real-time with huge processing power. However, 3d backgrounds are more dynamic and interactive.
This trade-off is what makes the recent kickstarter game
Republique interesting to me. Sometime during development, the team at Camoflaj stated that they transitioned from originally
pre-rendered backgrounds to full, dynamic 3d. Now, I'm not sure if all of the backdrops in the game have moved from pre-drawn to real-time, and I haven't been able to play the game yet, but just looking at it, you can see that the 3d backdrops with a static camera angle approximates the look of most games with pre-rendered backdrops. The camera isn't completely static though, as the player's viewpoint in the game is that of the myriad of pivoting security cameras placed throughout the setting.
Giant Bomb's quicklook:
http://www.youtube.com/watch?v=mRD-G4Im0jM
Look closely though and you can see aliasing and other signs that give it away.