I've only been able to read some of the posts on this thread - and they're great posts, most of them - but I'd still like to post my thoughts. I'll have to go back and really go through the rest of the thread, there's just so much to read! Anyway, I have stuff to say about straigth curious and bisexuals:
What people should know about curious straight guys is...
My understanding of curious straight, and what I felt I was before I discovered my bisexuality, is that a guy knows he's into girls but finds himself looking at guys... and not in the friendly way. He sometimes gets aroused by guys, but he doesn't see himself doing anything with them. He might even find himself looking at gay porn, or more at the cocks and bodies of hot guys in straight porn than the women, or at both equally. He could even go as far as to fantasize about a guy.
I felt that way, and it was some time after I started looking at gay porn before I realized that I wanted to do more than fantasize about doing things with guys. That was my transition from the straight curious phase to the bisexual phase.
What people should know about bisexuals is...
We are indeed capable of having real, strong, lasting relationships with a member of either sex, some of us are more likely to have those relationships with one sex than the other, but either is possible. Even if we are in a relationship with a person of one sex, we will still be attracted to people of the other sex, too. We won't necessarily go out and fool around, but we will get the urges and we will sometimes get aroused by the other sex.
Example 1: A bi guy is dating a woman. The relationship gets serious, they fall in love with each other and start having sex. The guy isn't just going to get over his attraction to guys, he's still going to look at them, maybe jerk off to guys in porn when he's not getting sex, but (if he's a decent guy) he won't go out looking for a guy to fool around with.
Example 2: A bi guy is dating a guy. Same situation, just with the other sex... relationship gets serious, fall in love, sex. The guy won't be magically not attracted to women, it will still be there, he just won't act on the impulses and go out to get frisky with a lady.
There is also a third scenario, the casual scenario. Also could be called the "friends with benefits" option.
Example 3: A bi guy isn't currently in a relationship, but he has both guy and girl friends that have fooled around with him before and are willing to do it again. Depending on his mood he will pick to go with either one of the guy friends or the girl friends. And just because he has sex with, say, a girl one night doesn't mean he won't go out the next night and have sex with a guy.
Note that this is for more centered guys, who are around 50/50 liking guys and girls. That brings up another point.
What people should know about bisexuals is...
Many of us are attracted more to one sex than the other, but we are still attracted to and will do things with both. It's not 50/50, just like straight guys aren't necessarily 100% attracted to just girls and gay guys aren't necessarily 100% attracted to just guys. The same could be said for women. It's also not a switch we can flip, to say "Oh, I'm on the gay side today." Our mood determines which sex we'd rather be with at any given time and there's nothing we can do to change our feelings at that moment.
Well, I hope this all makes sense. Just a window into my life as a guy who has finally opened up to his bisexuality.