As every fellow fangirl would agree, much of the appeal of animated Japanese pop-culture comes from the men. The juicy, sexy, pretty, strong, passionate, chivalrous men. Here are some of my top picks; I think many of my cohorts out there would concur:
Ahhhh, Sebastian Michaelis..... Smart, able, handsome, alluring, mysterious... evil. But in a good way. Being a demon, I'm sure he's more than capable of any number of horrendous atrocities, though the Sebastian we're familiar with in Black Butler is a "good" demon. His dedication to protect and serve Ciel at all costs makes him noble; and I dare say there's a bit of affection on his part for Ciel.
I'm anxious to see what he'll do when their "contract" is up - will he really devour the boy's soul? Or will he have a change of heart? I know what happened in the anime, but it is not in accordance with the manga and therefore, I don't count it.
Also, I just loved J. Michael Tatum's voicing of him in the English dub; his smooth, low cadence really added to the character (not to mention that he was the only one who could actually do a British accent...).

Grimmjow, another evil yet sexy demon-esque character. Somehow, Bleach was just never the same without him, Ulquiorra, and Nel, my other favorite characters. A Vasto Lorde Hollow turned Arrancar Espada, he may be crazy, but I think his appeal is pretty irrefutable.
I once read a blog post wherein the male author wrote that otaku girls love homicidal psychopaths. Hmmm... well given my top-two, I think he may be onto something...
Hagi, Hagi, Hagi. Probably my favorite vampire in fiction, Edward Cullen ain't got nothin' on him! His devotion to Saia, annoying though she may be, as her Chevalier is really beautiful. Despite having been in love with her, unrequited, for a hundred years, it doesn't discourage him one bit, at least, not outwardly. He stays by her side, watching and guarding, with no hopes of ever having his love reciprocated; he's happy enough just being with her. So romantic... *sigh*
Kakashi was my first anime crush. I've already written all about why,
here.
Although we spent much of the first half of Bleach hating Byakuya, after the Rukia Rescue arc, he became friendly and comical. I never found him attractive, though, until the final season,
when the animation and character designs changed. Unfortunately, much of that season was wasted on Xcution... I could have done with more of this Byakuya instead.
Only recently have I become turned onto Boy's Love & Yaoi - mostly manga, but I like them in anime form as well. Usually, I'll read the manga, then discover there's also an anime, and it's really fun to see the characters I've fallen in love with come to life.
Next on my list is Morinaga Tetsuhiro from Koisuru Boukun. He's so adorably sexy, sweet, and romantic, I wish he were real (and straight) so that I could date him. He's everything a girl wants: dedicated, handsome, selfless, unwavering, and he lives to please his partner. I could do without the making decisions on his own to disappear without a word thing, but nobody's perfect.
He's my favorite right now because I just love Takanaga Hinako's illustration style, but there are so many delicious men in Yaoi that I may need to write another entry just for them... Takano, Yukina, Nowaki, Ijuuin - ugh, there are just so many.....
Nura Rikuo is another big crush of mine. Although all of the 3 heads of the Nura clan are pretty damn sexy (well, Nurarihyon
was, in his heyday), but Rikuo in his night (youkai) form is just irresistible. Looking, sounding and acting more in his late-teens or early twenties, he's a far-cry from his 13-year-old human form. He becomes more the leader, take-charge type at night, which is really appealing, but he also still retains his human values and personality. He has a good heart, but is mysterious and strong. At first, the hair bothered me, but I really don't mind it anymore.
Brash, hasty, and headstong, is Gurren Lagan's Kamina. But he's also idealistic, optimistic, and sympathetic. With someone like Kamina on your side, you could never lose heart. He'll keep fighting till the end, and motivate you to do the same. Ah, how I missed him when he was gone... Simon grown-up wasn't too bad, either, though he was basically Kamina 2.0
Voiced by Daisuke Ono, who was also Sebastian in the Japanese version of Black Butler (Kuroshitsuji) and Shizuo in Durarara!, Brave 10's Saizou is your typical apathetic, dark, brooding, handsome type, though that changes a bit throughout the course of the show. I thought his personality shift made him less attractive at the end, but that's just my take.
By the way, there's something about these Shounen-genre guys that when they fight and get all bloodied up, it somehow makes them more attractive...
Heiwajima Shizuo may not have much of a personality besides being freakishly strong and hating Izaya, and I'm never really big on the typical, good-looking blonds in anime, but I can't help but find him attractive. His firecracker personality and his aloof demeanor make me want to know what he's thinking. Just don't get him mad, or you'll regret it...
Again, not big on those pretty-boy, blond types, but Miketsukami Soushi is another one
I just can't help but fall in love with. His undying devotion to Ririchiyo, if a little creepy because of their age difference, is nonetheless heartwarming. He throws himself at her feet, with no expectations of her reciprocating his feelings, and serves her without a second thought. He would never dream of pursuing her; he's happy enough just to serve her.... *sigh* Where are the guys like that..?
So in conclusion, to be found attractive by an otaku fangirl, you must:
1. Be a little evil and psychotic.
2. Have an undying, unconditional love for a woman who may never love you back the same way.
3. Either a) relentlessly pursue your love until they love you back, or b) swear your service to your
love unconditionally and find fulfillment by just staying by her side.
4. Be mysterious (maybe even wear a mask).
5. Have a fighting spirit that burns and motivates till the end.
6. Get bloodied-up.
Good luck, real men!