Hmmm...this is suprisingly hard...so many I just can't decide--so here's for guessing! (like you, I'm sure I'm leaving some out because they didn't come to mind immediately...)
1. Teru (Dog Style)
2. Havi (Crimson Spell)
3. Morinaga (Koisuru Boukun)
4. Usami-san (Junjou Romantica)
5. Takano (Sekaiichi Hatsukoi)
6. Yukina (Sekaiichi Hatsukoi)
7. Yoshioka (Sorenari ni Shinken Nandesu)
8. Ayace (Corsair)
9. Takumi (Hana*Koi)
10. Taiyou (Kimitachi Otoko no Ko)

1.kato youji(haru wo daiteita)
2.sonic the hedgehog(sonic x)
3.dee laytner(fake)
4.usami akihiko(junjou romantica)
5.roy mustang(fma)
6.yoite(nabari no ou)
7.kusaka touma(winter cicada)
8.hiroshi nakano(gravitation)
9.takano masamune(sekaiichi hatsukoi)
10.gii(takumi-kun series)

After putting and replacing many, I present you, my top ten (not in order):
1. Iason (Ai No Kusabi)
2. Havi (Crimson Spell)
3. Asami (Viewfiender)
4. Morinaga (Tyrant Falls in Love)
5. Miura Tomomi (Darling)
6. Kuro (If Dogs Could Walk)
7. Mookyul (Totally Captivated)
8. Ayace (Corsair)
9. Masamune Takano (Sekaiichi Hatsukoi)
10. Eclipse (Demon Diary)

1 Craig [sp]
2 Hikaru [ohshc]
3 Kakuzu [naruto]
4 Shizou [durara]
5 Sasuke [naruto]
6 Stan [sp]
7 Sebastian [black butler]
ca't think of more...

littleyaoigirl what does sp stand for?

Very difficult indeed...T_T

*Asami (Finder Series)
*Mookyul (Totally Captivated)
*Aikawa (Mujihi na Otoko)
*Usagi (Junjou Romantica)
*Takano (Sekaiichi Hatsukoi)
*Shinonome (Kirai ja nai Kedo)
*Morinaga (Koisuru Boukun)
*Togawa (Doushitemo Furetakunai)
*Havi (Crimson Spell)
*Soubi (Loveless) Although he is a future seme...:P