I've just returned from my polling place in Arlington, VA (South Arlington, west of I-395) and there was a constant stream of people into the polling place. Things of note:
My wife went at 8AM this morning and there were >50 people there, and the wait was an hour long!
I went at 10:45AM and there were ~30 people in front of me in line to vote.
It took 25 minutes for me to get to the front of the line.
The length of the line stayed a constant 30 people deep the entire time.
From my very unscientific observations while I was in line, the ratio of Democratic ballots to Republican ballots taken was about 7 to 1, but our neighborhood (and in fact most of Arlington) is very Democratic.
The age, economic, and racial makeup was all over the map, I saw it all as I waited, very encouraging!
So if nothing else, it appears that people are are at least involved, and this bodes well for the Democratic party in November!