Whichever fighter I like more at that point in time. More often than not it's the underdog, but it switches. Doesn't mean I don't appreciate a good performance by the other guy though.
None of the above .... I generally root against Floyd while I'm from US/smooth black/and right handed
If a boxer's Jewish I'm more likely than not to root for him. I also tend to like more skilled back foot boxers than agrisive presure fighters. When scoring a fight. I try not to let this get in the way.
I purposefully left out that option ... because I didn't want people to have an automatic defense mechanism of "I'm not biased" and click "none of the above" without at least considering the options. I should have added "underdog" to the list though.
None of the above... I'm mostly influenced by style, record, personality, and if I feel the fight is an obvious setup to make one fighter look good and the other fighter look like an opponent, in which I often root for the underdog if it isn't a prospect I've favored previously.