Panther.
Humans. Female humans.
I’ll go with the human species, male subset, thanks.
It’s definitely somthing in the cat family, but I think all of you folks saying “Cheetah” might be unduly influenced. Myself, I’d say probably the panther, or possibly the tiger.
Those female cats from the play of the same name always get me going…
I wonder how many of those women have brought that costume to bed…
grrrrrowl
Sexiest animal, eh? Hmmm. I once inherited a parakeet named Sam who had been taught to say things such as “Hi there, honey” in a remarkably seductive voice - followed by a wolf-whistle. I was single and horny at the time, and I must admit that there was something vaguely arousing about hearing this bird going through his routine.
It would never have worked between us, though. I’m white, and Sam was green. Also, he weighed about three ounces, and if I’d rolled over in bed I would’ve squashed the poor little bastid.
Role up Role up, come see the closeted furries, don’t get too close though as some of them bite (or worse!)
I have occasionally been known to be an ass man though.
Otters. They’re sleek, they’re muscled, and they just look like they’re having so much fun.
Not that I practice otteroticism, or that I’m wanting to get it on underwaterstyle. But you asked.
Daniel
ahem 
I’m to sexy for my cat. What do you think about that?
Tigers maybe. Or the blue shark. Sometimes bunnies.
Google for “Omaha The Cat Dancer”. But…not at work!
I don’t know about sexy animals, but I just melt when I look into the eyes of a husky.
Naked mole rats? they’re naked!
wait no, better yet…MANIMAL!!! oooooh ahhhhhh! 
[Anya]
Bunnies aren’t just cute like everybody supposes,
they’ve got those hoppy legs, and twitchy little noses.
And what’s with all these carrots,
what do they need such good eyesight for anyway! …
[/Anya]
I’ve been looking for an excuse to post this all day, thanks Inigo!
Why hasn’t anyone mentioned the fox?
Have you seen a live fox? They’re usually pretty mangy-looking - kinda like a short, reddish coyote. And they stink!
Dolphins are sleek and graceful but I hear they are only into watersports.
As tatoos on females, jaguars and butterflies.
I’m overly disturbed by this question due to the fact that I’m watching the Furries/Plushies episode of CSI. THERE IS YIFFING.
I may have an answer later when my brain is cleaned.
I’d just like to point of how disturing the ad on that link was. It was a Smoky the Bear add. With Bambi featured.
My mind hurts.
Ew! Ugh! You’re watching CSI?
I was going to nominate cats, but the tone of this whole thread has left me unsettled.