Favorite: Jim Baw. Without a doubt the most knowledgable dude on this site. Just read his posts...well reasoned...doesn't need to resort to name calling to try to make a point. I respect that.
I also really enjoy Crackcat and Roadkill for remembering that sometimes we all just need to lighten up. Packersfan, Lemony, Sassy, Jenna, Rob, and a ton o others also try hard to keep it real on here. Smart users...but they aren't full of themselves, like somefolks on here are.
Least Favorite: Reportes, trolls, cloners, and those people who are full of themselves, or think that "Colts Rule, Raiders Suck" is somehow an inciteful answer (and even moreso to those who pick those answers for BA....).
And I gotta list those who take every criticism of their team as a personal attack, no matter WHO they root for, and try to start smear campaigns, because they can't "prove" their points any other way. It's just football people... I love it... but I do have a life! (well...sorta)