Tokyo Game Show 2005
I went to Tokyo Game Show, and while it was fun, it's definitely smaller than E3, as I was able to see everything I wanted in only one day.
It was mostly worth it, even though PS3 wasn't playable, I did get to play some good stuff though, and man was there a tonne of stuff for mobile phones.
That night I also started to pack / try to figure out how to tetris all the games I've bought into my luggage.