Thank goodness we don't take into account the possibility that bisexuality is not equivalent to cyclic or targeted sexual interests. I swear if we could slap a label on anyone it would be "Bi", particularly because we simplify, and oversimplify, romantic and sexual attractions.
Sexual attraction isn't even really based on physical attraction alone, that's a myth, so you don't have to be physically attracted to someone to be sexually attracted to someone thus killing the infamous "Everyone's Bi!" notion instantly. Asexuals are sexually attracted to other people, they have a sexuality and do maintain some level of relationship, but the physical person may or may not hold any particularly physically attractive traits.
So, if you like guys and girls, but shoot more for personality than looks or acknowledge looks but are not drawn solely based on looks you're about as bi as a buffalo can be. No, buffalos cannot be bisexual. :/