She can't get enough.

Name: Tokugawa Sen
From: Hyakka Ryouran Series

Being a fan service anime at its core, you should already know what to expect from the "Hyakka Ryouran" series, especially with character designs like Sen. She is the definition of a big breasted high school girl who just can't get enough of the protagonist. While there are plenty in the series with nice tits as well, Sen is the one that makes it count the most, because she has easily the most fan service scenes. Well, you can't complain, with someone as sexy as her. If I had to choose from the entire cast a girl with the most sex appeal, it'd be Sen.

The proportions are enough to get you on.

Name: Bullet
From: Blazblue:Chrono Phantasma

One of the newest female additions to the "Blazblue" cast has got a lot of people steaming for more. Bullet is as sexy as they come, with a character design like that, she would be sure to attract many players. I mean, just look at her, she's about as busty as Litchi, but with a sexier face and a more revealing get-up (one can argue that Litchi's outfit is also revealing, but come on, just look at Bullet). With pants that short, she might as well just not wear them. Plus, the way she jumps around doing kicks and stuff....what can I say? If you haven't seen Relius's astral on her, I recommend it (*wink*).

Megane bishoujo!

Name: Satellizer El Bridget
From: Freezing Series

Why do people watch "Freezing"? For the most part its because of the series' cover girl, Satellizer El Bridget. She has the most revealing school uniform apart from all the other students in the anime, she is sexy as hell with just her body alone, and she goes all "dere" when Kazuya decides to do anything to her. Nothing turns anybody on more than a fierce, defiant girl like Satellizer become as timid as a mouse when she's not in her territory. To make things even better, there are tons of fan service scenes surrounding Satellizer, with her getting stripped most of the time. Its like they want us to look at her and only her, not that I complain, I'll take Satellizer over anyone else in the series.

In that state, I'd be aroused as f**k

Name: Yuri
From: Angel Beats!

Yuri was one girl that didn't really get all that much credit for her sexiness, with all of that being thrown at Kanade. Sure Kanade was cute in her own right, but for the sexiness level, its Yuri that manages to pull it off nicely. With her personality, she was already plenty attractive in combination with her looks, easily the sexiest in the anime. There were certain service scenes with her, but since "Angel Beats!" isn't centered around fan 
service, it was all up to our minds to fantasize. Still, I would definitely hit on her, though in that state, she just looks all the more sexy.

Just be the cupid.

Name: Elf
From: Dragon's Crown

With all the overheated debate and love for the Sorceress AND the Amazon (wtf world), the girls in "Dragon's Crown" already got their placement. The Elf is the least popular, but to me, the Elf is the most attractive out of the cast, because lets face it, the Sorceress and Amazon are a little too out of hand (especially Amazon). Being voice Asami Imai is one thing, in a fantasy setting with no characterization like "Dragon's Crown", its easy to fantasize, and since the game includes animations for your characters in various situations, its easy to...picture it in your mind (the "captured" animation, for example). The Elf is beautiful, her clothes aren't the most revealing like her other 2 female counterparts, but she wins in the art of everything.