I got back from GDC a couple of weeks ago with a couple of regrets. Firstly, I ate way too many Karl's Jr Hamburgers, secondly I missed way too many awesome presentations. Thankfully I can now watch (some) of the presentations for free - and so can you.
If you head here, you can get access to Satoru Iwata's keynote - where he rags on mobile gaming! - a Bejeweled retrospective, and a presentation on Doom by John Romero. There's also plenty of other content to peruse, from overseas GDC events and presentations from past GDCs.