I have to say that something's really wrong with your TV in that case... I've played it on SDTV, HDTV and a projector and I've never seen any issues with blurring / loss of detail.
QFT
You can say Halo 3 has jaggy issues (I wouldn't call them issues, but jaggies do exist). However, the game is as sharp as a tack. No blurring problems over here. Probably just the guy's TV.