I got in line, also in PG Maryland, at 0645, and voted at 0930. Long uneventful wait; I had brought a folding stool and a good book. If somebody had come down that line selling hot muffins and coffee, they could have made a mint.
I was also surprised that no ID was required; I was asked for my first and last name, at which point they printed out a chit with my name/bdate/address/affiliation on it, and I had to sign that. The touchscreen device was easy to use, but I agree that it'd be very easy to jigger the innards to produce any result you want.
On my way in to work I was listening to NPR's Dianne Rehms Show on the election; one caller (I believe from Virginia) said that when he arrived to vote today he was told that he was on record as having already voted by advanced ballot. They had him fill out a provisional ballot and verified his signature while they researched the issue. I would be afraid of just such instances if early voting becomes more common -- I voted against that ballot initiative for MD.