Yes, my best friend is straight and I've fallen in love with him twice already.
I mean, even though I know there's absolutely no chance of being in a romantic relationship with him, he's just that awesome that I can't help but fall in love with him.
I also have two bff's at work, one of them straight (although both of us bi's always give him a hard time by accusing him of otherwise
) and he's pretty awesome.