Joe6Pat: You've touched on a fundimental oddity of the Pats O-Line. EVERY YEAR they change from being a good run team to a good pass team.
I think it has to do with what they emphasize each offseason. After all, these guys are not 'world beaters' on the O-line, they are just hard workers who get a lot of training, and whatever is drilled into their head each offseason seems to be what they are good at next year.
2001: Good run game that made A. Smith look good.
2002: Led league in touchdowns, no run game.
2003: Not too great in pass protection, Brady's worst year.
2004: DILLON!!!!
2005: Led league in pass yardage.
2006: DILLON, MARONEY!!!!!