If you're looking for a place to get a drink near TD Garden, check out these places...
http://www.boston.com/thingstodo/gallery/gardenarea/
I've been to The Fours (named for #4 Bobby Orr) and it was very cool. Tons of Bruins/Celtics memorabilia, lots of beers and tv's as well. And yes, even non-Bruins fans are welcome.