I'm a straight male by natural preference, although I've chosen to act in a manner more consistent with asexual. (Five years sex free now, although I still have my moments of weakness, none of them have caused me to give in yet.) Asexuals have made it clear that I'll never be one of them, so straight it is.
Also, I kinda feel like a jerk saying this, but it annoys me enough I want to say it anyway: This whole thing about pan- or omnisexual is really just a bunch of silly semantic garbage and I wish it would go away. There are only two genders, and bisexuals are attracted to both of them. Hermaphrodites are exceedingly rare, and anyway they're simply people that are physically both genders. Conveniently, bisexuals are attracted to both genders, so they've still got it covered. Transgendered people were born with one set of genitalia but identify with the other gender. Anyway you slice it, they still belong to one gender, the other or both. Again, bisexual has it covered. I appreciate that you want to emphasize your open-mindedness, but is it really necessary to make up words to express it when there's already a perfectly serviceable word that covers what you are?