Unwanted Attention

Do I have "come talk to me, I have low standards" written on my forehead?
Or am I just that lucky?
Before I continue, I should say that I realize it has to be hard for a guy these days. But after being turned down multiple times, you'd think they might take the time to evaluate the situation and either take a new approach or no approach at all.
So, back to the story. I'm waiting for my husband to pick me up from work yesterday and I decide to head down a little early to bask in the sunlight. I'm waiting near a bank for about 10 minutes when a short, chubby, middle-aged man approaches me. Only I don't know he's there - because he is standing behind me. Then out of nowhere I hear, "who would have such a pretty lady as you waiting outside for so long?"
I turn around in surprise to find said man with a sleezy smirk on his face.
I politely smile and inform him that I chose to come downstairs early for the sun. He takes this as an indication that I am accepting his advances. He moves closer. "You know, there are coffee shops over there..."
(internal remark: I know, we're in Fucking Seattle!)
me: (insert awkward laugh) "yes, I know. I work here." (bad idea)
him: "oh? you work for ____?"
me: yes
him: "which department?"
Trying to control my growing irritation, I respond in as few words as possible.
He then goes on to tell me that he works in a similar department and would love to talk to me about it.
So here's where I tell him that I am not qualified to answer specific questions about our tool process and thatI could give him the email of a person willing to help.
The rest of the story consists of him taking down the email address of said co-worker and then me taking every opportunity to turn my back to him or ignore his questions.
Part of me feels bad for being so rude, but then I remind myself that I did not welcome his attention.
Now, I'm not saying that a little attention is always a bad thing, but this type of thing happens to me more often than I'd prefer. And between you and me, they're RARELY good looking or even self-confident. It is because of their obviously tender egos that I find myself being polite but I really just want to tell them to fuck off.
Any suggestions on how to handle these situations would be greatly appreciated.
Thanks in advance. :D