As one more female weighing in to the debate, I do appreciate compliments that are sincere and made in a non-threatening way. I've noticed the descriptors "creepy" and "threatening" come up in more than one response to this thread.
Since you're addressing women on the topic of "unanticipated flattery", I would beg to quantify this phenomenon into three groupings: absolutely sincere recognitions of physical beauty/health/youth/defiance of age/intelligence, overtures in a non-threatening manner, and creepy/street harassment.
The most genuine compliment I received lately was at work, when someone told me "you have the most amazing eyebrows!" It was, perhaps, slightly unorthodox, and coming from a woman, so I was happy.
In a bar/club/coffeehouse/on campus, I'll get guys who compliment me and do expect to follow up to something more. After hearing that I'm not single, some of them stick around to talk to me like an actual person, others trail away in a non-creepy manner. I understand that if you're looking for a lovemate, I might be a waste of your time, so I don't judge the slinkers.
But street harassment, or compliments that happen in a setting of unequal power relations, are decidedly creepy and not appreciated. I'm relatively attractive (much of that is youth and good genes), not super-beautiful, but I get "holla'd" a lot. Sometimes, it makes me afraid to walk by a group of men if I'm walking down the street. I used to smile or just say "hi" in hopes that these guys would just leave me alone, but that seemed to provoke further comments on my physical attributes/my friendliness/my fuckability, so I've decided not to do that so much. The thing with the street harassment is, that now that I don't smile or acknowledge it in any way, I always (every single time I've done it) hear something along the lines of "uppity bitch" or "we don't like the stuck-up ones anyways". You know what? I'm just walking down the street, trying to mind my own business.
So, dude, it is kinda different for women. Sometimes, it's genuine, but sometimes it's a challenge to your ability to walk down the street minding your own business, or being able to do your job without having to hear from married middle-aged men how beautiful you are, how that outfit looks hot on you, or having air-kisses blown your way (all of which have happened to me at work.)
I do love having sincere compliments, but the other baggage gets in the way.