Would be awesome to open a chest and actually see its contents laying in the chest. You have to remove each item separately or open to find it filled with useless garbage and have to find its secret panel etc. Would be much more engaging than the list of items that all RPG'd seem to use.
Ultima Online did this way back in the day. The only difference is that since the game was an overhead third person zoomed out camera viewpoint, the opened chest would appear onscreen as an open container after you opened it, allowing you to loot the contents. You had to move things around to find the stuff below the other items. Of course, all inventory was like this, including your own backpack.
An example: http://www.aschulze.net/ultima/screens/477.jpg
Granted, the treasure chests in UO were mostly garbage, except the ones you got to dig up. You'd get really great stuff for taking a map you got off a monster, using the cartography skill to decode it, sailing around the world looking for the land mass depicted, digging the treasure up, fighting monsters as you continue to dig, and finally picking the lock after slaying some of the more difficult monsters in the game.