Yes, I walked alone at night, in Roxbury and didn't die. Not even close! In fact, I had a fantastic time at a bar just a couple blocks off of Mass Ave. The bartender, Joe, is a born-and-raised Bostonian who can talk your ear off about the history of the city and the South End. He showed off pictures of his dog, who he's, apparently, been to every national park in Massachusetts with, and has the stamps on his national park passport to prove it!
The drinks are decent, cheap, and appropriately dive bar-ey -- all forms of light and regular cheap beer, Coronas with lime, an assortment of liquors mixed in your choice of half a dozen mixers (with 1.5 shot pours!)
The place where Chin's really stands out is the food (served from 11am to 10pm) -- They don't have a menu, it's more like "Whatever the hell the cook feels like making that day." I had fried pork belly -- yes, this is basically like fried bacon chunks -- and it was divine. There's a lot of soul food going on here, bean and rice, pork and meats of all sorts -- unusual for a bar, but it works with this place.
If you ever get tired of the Tam, head out just South of the South End to Chin's. Solid 4 star dive bar!