How would you handle

Damn, he sounds SO much like one of my neighbors. He has no social skills or common sense of things like invading someone's space and time. I nicknamed him Milfoil, because he is an invasive species, like milfoil is.

He NEVER goes away on his own when he drops by. I ALWAYS have to eventually give him the boot. He ends every sentence with "and" or "but" and then leads it right into another sentence, never giving me the opportunity to chime in to say a word or to let him know that I don't have time to talk. ARGH!!! I get a little angry just tying this!
He will talk about the stooopidest stuff endlessly and it drives me nuts. I really feel for ya. I have told other neighbors that if you see a for sale sign stabbed into the ground in my front yard, it's because of THAT guy! I have been very very direct with him in telling him that I don't have time for drop-bys and social stuff while I am working. It has helped some but he will never really "Get it"...
I don't want to start a war with any neighbors so I keep it civil and bite my tongue. A lot.
My condolences to you!