Having seen the Halo 3 and Killzone 2 trailers, I would say they are both as equally impressive as each other. Yes the rendered 2005 trailer did no favours, but the realtime trailer is shockingly close, and definitely exceeded everyone's expectations, especially after that screenshot. It goes without saying I was caught offguard by it, and I am sure many others were too. Coversely, Halo 3's trailer seems slightly underwhelming, graphics-wise. It definitely captured the 'epic' feel of the series as a whole, but not state-of-the-art graphics at the time like the first two games in the series were.
I haven't seen any other presentations, but I heard Mass Effect is supposed to be pretty amazing. Are they showing Gran Turismo 5/PSP this year?