Since the discussion has already branched out (well, sort of) to other American sports I'm going to take a bit of a liberty and go off on a tangent.
First of all, Basketball: I don't get it, never have gotten it and never will get it. It is hard to imagine a sport that fails to pique my interest in the same manner that basketball does. I couldn't bring to mind a single player beyond the small cadre whose names are inescapable as their profiles transcend the bounds of the sport (Michael Jordan, Dwight Howard, Kobe Bryant et al).
American motor racing doesn't sit well with me at all, NASCAR, for example, should be banned. Sure, I respect some of the drivers and recognise their talent but come on, stock cars bore me to tears. Real racing is about actual racing tracks with technically challenging corners, Formula 1, DTM, V8 Supercars, not a succession of circles with little differentiating them beyond slight variations in gradient. Don't even get me started on drag racing, tedious, tedious, tedious.
I've had a casual interest in the NFL for a decade plus, following the Colts and enjoying seeing Peyton Manning tearing up the league every year before falling short in the playoffs more often than not. Nowadays I await Andrew Luck's transformation into Manning 2.0 (wishful thinking, perhaps, but he surely has a Super Bowl in him).
Baseball doesn't appeal to me, although I am fascinated by the history of the sport and the wider social context of grassroots play outwith the major league (thank you Ken Burns). I usually catch a game or two of the World Series every year.
As for Hockey, which of course isn't an 'American' sport as such (unless one is using the word in the continental sense, i.e. North America), I'm rather enamoured with it. The speed, the skill, the hits, the physicality, the technique, the culture, the passion, it is ever so similar to football in many ways. The Montreal Canadiens are my favourite team.
Apologies for my rambling.