This one's hard. Really hard. Now...
Dean Winchester would be fun, he'd be great for spending a night of doing things you never would and as Lisa Braeden once said, he'd make it a night you remembered for the rest of your life. But then when morning comes, he'd put on his clothes, at best he'd take your phone number with him and the chances of ever seeing him again, would be smaller than the chance of winning the lottery. But man, would it be worth it!
Spike, ... also great in bed, but... unless he's actually in love with you, he'd basically be the same problem that Dean has. Losing himself in fun and sex and then you'd have to worry about him saying Buffy, Drusilla or Angel's name when he comes. Well that and great looking as he is, I think he might be a bit cold.
That and his idea of taking you out on a date wouldn't be too good for my diet. Fried onion rings might be tasty, but man the fat in them...
So I basically can come up with one last person, and the person I'd probably have most fun with.
Peter Parker. Not the Brand New Day version. Him, I would willingly throw under a bus *is disgusted*
But the real Peter Parker. The adorkable lost little boy who didn't quite know how to deal with women but tried his best. The hero who took care of his aunt, because she was all he had left. Responsible, kind, selfless... He might be late for pretty much every date you have with him, but you know that he'd do anything to make up for it. He's not a Don Juan, and he wouldn't have quite as much experience as the other two guys, but he'd be so damn earnest about it and you'd know that when morning comes, he'd be lying there next to you with that geeky smile on his face. And he'd be the one not quite believing how lucky he is, even though you know that really, you're the lucky one.
He'd take you to places around the city, and the webswinging would be awesome. And most of all, he'd love talking about sci fi movies and geeky stuff and be as much into them as you yourself are. (well if you're me at least)
So yeah, dating wise, it'd definitely have to be Peter. Too bad that that one belongs to MJ ;-)