Well, the mind is number one. But if we’re going for purely physical, it’s the face. More specifically, their expression (I think those “hot or not” websites are stupid). A woman looking at you with affection is the most erotic things there is.
This.
(link ~ 91% safe for work)
[del]Boobies[/del] I’m probably not looking up high enough to notice if she has any
[del]Thigh[/del] Not the focus
[del]Buttocks[/del] nope, turn around please
[del]Leg[/del] look higher
[del]Vagina[/del] not in isolation and not as you probably mean it
Also not the navel (nice if it’s included in the viewing angle though) not “camel toe” (again, not that localized and specific), not the hips (that’s, umm, the picture frame, but again that’s not the focus)
I dunno what you call it. But yeah, there.
I appreciate the inflatable aspects of a good woman (might not be safe for work).
Lips.
Fingertips.
I’m a leg man. Preferably two legs…
While I voted for legs, I find a well-formed pair of clavicles intensely attractive, along with shapely hollows of the knee. But I’m a strange duck.
Yes. I can agree with this.
Your hotlinkfu is weak.
The link is correct. The site doesn’t allow direct linking. Copy and paste it into a new tab/window.
Boobs, moving ones in particular. Just this afternoon I admired the scenery of a well-endowed lady jogger while waiting for my bus.
While the top two contenders don’t surprise me, I’m surprised at the low number of votes for “thigh” and “leg”. Personally, I’ve always called myself a leg man, but mostly because “thigh man” sounds like you’re either talking about chicken or are just crazy.
There’s nothing better than roll-up denim short shorts and a halter top. Miniskirts are fine, but overrated and often oversold by the wearer. I’m convinced that Capri pants were invented just to piss me off.
Second would be the butt, Bob. As for boobies? As the saying goes, more 'n a mouthful’s a waste anyhow. :o 
I have a hard time understanding this. To me, and the dictionary, erotic means “tending to arouse sexual desire or excitement.” If I found women’s faces as erotic as their breasts, asses and vaginas, I don’t think I could interact with any women.
For instance, my assistant is very pretty. But I don’t find her face ‘erotic’ and I’ve never been aroused by her. When we talk, I look at her face, very rarely take note that she’s pretty and never ever think arousing things about her face. We get by just fine and I’m certainly not holding back wild erotic urges every time I talk to her because I don`t find faces erotic and I’m not a pig. On the other hand, if every time I needed something from her she lay naked on my desk with her legs spread, even I would be aroused by her erotic vagina in spite of my best efforts to remain professional.
I guess I’m just lucky I don’t find women’s faces erotic. I don`t know how the hell you guys get anything done.
See, that’s why you’ll never find anybody…you’re too picky.
You’ll never get laid if you’re going to be so picky.
Boobs - love 'em. Petite and perky the ideal. Nice round butt like a Georgia peach? Yum! Legs? Wrap 'em around me, baby. Vagina? Gimme two! Still and all, for me, nothing beats a nicely puckered butt-hole. 
I didn’t say pulses were mandatory.
Beav.
Here it is: http://www.worldofstock.com/slides/PMO4258.jpg
I like boobs. But I also like necks, both slender ones and pleasantly-plump ones. There’s something about a slight double chin that just turns me on… it hints of curves elsewhere. I also like wide hips, a square chin, a stocky build, a dark complexion. I also like petite elfin women with big eyes, so go figure. And long hair. Or short hair. And asians. Or redheads. Or brunettes. Or a certain type of mature blonde. And dark curves. And pale skin. And golden skin…
Oh heck. I like 'em all.
I wasn’t going to post, but since no one else picked this.
I like shoulders and upper arms, if they are nicely toned. Sleeveless blouses are fantastic. All the other stuff is good also, but shoulders are the top.