[Evil_Duckie]

It does make a difference where in this country you are (obviously a different part than where I am, as I haven't seen any clogs, tulips or Grolsch today...). If you're in Amsterdam, go by bike. The reason is that everybody else in traffic there fears the bikes. Whenever I'm there, bikes do kamikaze attacks on me, whether I'm walking or driving my car.

Apart from that, I'd say walk. Fresh air does you good and you simply get more of it if you're outside for a longer period of time.