All I can say is keep checking on the DSL and if it ever becomes available, drop Comcast ASAP. Verizon DSL in MD can be had for $30-35/month. There is a website (I think it is www.dslreports.com) that is helpful to find out how far you are from the nearest station.
Not unless I can get DSL at the speed of 1 Mbps (and Comcast will soon be upgrading it to 3 Mbps). I don't think residential DSL can approach the speeds I am getting now. The last time I checked, if I were able to get DSL, the max speed Verizon was offering for residential was 384 Kbps.
Plus, I don't think it is a distance issue for me. It's because of the way the phone lines are run to my house. The lines go through a "pair gain" that lets the phone company multiplex the lines, if I understand correctly. This prevents DSL from working, just like it prevents me from getting a ~56K modem connection.
But I'm not sure I'd switch anyway. I'm paying $49.95/month for 1 megabit (and it's supposed to get upgraded to 3 megabits soon).