We just bought a house within biking range of both of our offices. Yet we both really like spending 1 day a week working from home.

1) getting away from coworkers and the office allows you at times to focus on the actual work you're doing.

2) we have a kid and extended family who live nextdoor, so having family around is good, but they're distracting.

3) change of pace ... nice to be able to do yoga at lunchtime without worrying about changing/etc.