I am. I have a short (10 km round trip) commute that I pretty much treat as if I don't do it. My normal schedule is: Monday off, Tuesday - one hour run hard, Wednesday 30 km cycle (on top of the commute), Thursday one hour run easy, Friday one hour run easy, Saturday 20 km easy cycle plus 1 mile swim, Sunday 2 or 3 hour run or cycle (2 and 3 hours on alternate weeks). In the winter I drop the Wednesday cycle and replace it with another one hour run.
I usually do two marathons and an olympic distance tri each year (tri was yesterday) plus some other long event (2 week bicycle tour, 64 km run, back to back centuries have been the most recent). The commute, which I started about 6 months ago) doesn't seem to have affected the training. If I had a longer commute I think I would alternate longer and shorter training sessions (every second day I would only train for half an hour in addition to the commute).
All my weekday training is done after my commute and I don't worry too much if I miss a day every two weeks or so. The last marathon I ran was after a week of moving furniture to a new house that completely screwed my normal taper before the run and I still managed my normal time (3:45 ish).
I'd say, if you feel like you need the rest, take it. My worst marathon time ever was after over training.