1.) Gaius Baltar (BSG) - Yes, he's smoking hot, but have you noticed the CRAZY? Also a short-sighted, narcissistic, selfish prick.
2.) Duncan Kane (VM) - Leaving aside the obvious age difference, he's (in the words of Josh Lyman) a hairdo. A dull-as-a-doorknob cardboard cutout with about as much personality as a sea sponge.
3.) Jack Shephard (Lost) - I'm pretty sure I'd have to kick him square in the balls within five minutes of meeting the guy, and what good would he be in the sack then?
4.) Gob Bluth (AD) - Funny as hell, but a sensitive, gifted lover? I'm guessing no.
5.) Sam Seaborn (TWW) - Yes, he's adorable, but just... no. Even if he didn't have any Rob Lowe in him, Sam falls squarely in the Friend Zone.
6.) Simon Tam (Firefly) - Too uptight. Too timid. Too dull. Too neat. Too preoccupied with his sister.
7.) Luke Danes (GG) - Two years ago he would not have been on this list. Today? I can barely look at him without feeling vaguely nauseated. Thank you GG writing staff.
8.) Charles Bingley (P&P, any version) - I mean, really, who would? Doesn't matter how much money he has, you'd always be dreaming about that steamy best friend of his.
9.) Preston Burke (GA) - See Simon Tam above, re: too uptight; too neat. Also too intense and too cold.
10.) Rupert Giles (BtVS) - Dude. He's Giles. It's like doing it with your dad. And I think I just threw up a little in my mouth.