The Giants, although I'll be much more conflicted than I was in 07.
Giants fans have taken a turn for the douchey ever since Rex came to town. They absolutley hate him and his talk (and our success the last two years while they struggled) so they've been pretty unbearable the last two years. In 07 it was a no brainer (Giants hadn't won in forever, Pats were trying to go undefeated, etc) but it's harder this time around.
Gotta be the Giants though. While I hate them, it's nothing compared to my hatred of the Pats.