The most interesting thing to come out of GDC for me is the Modern Warfare 2 trailer. It doesn't excite me in any other way other than the fact that is coming out. Jarvis and I talked about it on his podcast which you will get to hear in a couple of days but basically I haven't completed the first one so I will have to get to that. Here is that trailer:
The only only other thing that I wanted to mention is the OnLive platform. Everyone (Joystiq, Jarvis, etc.) has high hopes for it but I am sure but without an insane amount of money it doesn't look like it will ever become profitable let alone get off of the ground. Maybe I am being shortsighted on this one but I like my physical console and I do not think that everyone is ready to give that up just yet. I will give it a shot but I think it might just be a fourth console and not the end all be all of gaming. It is gaming from the cloud like we have been talking about. Let us just see if we are there yet.
An honorable mention of GDC is Zelda: Spirit Tracks, which looks like it used all of the assets from Phantom Hourglass and added a choo-choo train.
Off the top of my head that is all I can think of. I think I have a hankering to play COD4: MW now... funny how that works.