My favorite thing about my commute is a friend also commutes and every Friday we go out for lunch and do a 10 mile ride, stopping at a deli for a sandwitch and then stopping in a park...
It is a plesant break and a way to get the proper mindset for the weekend...
Oh yea, we usually kick it up a notch on a few streets
I do find that the commute, albeit slower than my weekend ride, does help keep the fat off...