Currently, I've indicated that there is a small keg of something poisonous, and a quick peak at the MIC suggests that an Exploding Spike (possibly reduced in level/price slightly to allow for more stuff) would be fun. I also think I'll include maybe 1-2k of more liquid funs like art objects and gems. There will also be a significant amount of mundane (or maybe masterwork) weapons and armor, which may or may not count towards the overall wealth limit since it would be harder for the players to unload.
So yeah: what are fun bits of general-random gear to put in a looted warehouse for a group of 7th level PCs? :)
EDIT: To clarify, because it seems to be needed: I'm trying to come up with a number of "little" items and things to give the PCs--ones that don't necessarily have plot hooks attached. Rather than one really awesome item, I'm trying to come up with a number of kinda-neat items.