I actually enjoy my commuting time. I listen to podcasts or think about what I need to do when I get to work (or home). If I'm on my bicycle, I find that my mine really wanders and I enjoy that.

Once I'm at work, I get down to it and am good for about 4 hours or so (on good days) of really good work. Spend an hour or two on email, light reading, talking to coworkers, and that's my day.