The Tokyo Imperial Palace is one of those places that ended up on our "maybe next time" list - you know, like how every trip to Tokyo has a few of those! While it's probably the most important building in Japan (it's where the Emperor actually lives), most visitors can only see it from the outside - lots of impressive moats and massive stone walls, but the real action is off-limits.
From what we've heard, unless you happen to be there for New Year's or the Emperor's birthday (when the Imperial Family makes public appearances), you're mainly looking at the famous Nijubashi bridges and wandering the East Gardens. It's kind of like Buckingham Palace that way - lots of build-up, but most of the time you're just imagining what's going on behind those walls.
If you're a history buff who's fascinated by the fact that this was once Edo Castle (basically the power center of feudal Japan), it might be worth the trip. But with so much else to see in Tokyo where you can actually get up close and personal, we weren't too broken up about missing this one.