Non-DUI response:
I, too, got back into cycling, if not commuting, due to poor health and largely because of alcohol consumption. Commuting to school while between jobs and in a career change was part of it, then road riding, the club riding, and commuting to work which is halfway between my home and the club ride location, was a natural evolution. I now ride about 200 miles a week to and from work, club rides and on the club rides themselves.

DUI response:
I also stopped drinking and driving (always "being careful", but occasionally pushing the limit) after a good friend got a DUI and lost his license for a year. He rides as much as I do, but ended up commuting for 6 months until he got driving privileges for work. His lesson learned: bicycle commuting by choice is awesome, bicycle commuting with no choice is horrible. I was pulled over and tested on the side of the road not too long before his incident. Those two combined were enough to convince me, it just ain't worth it.