For me, 25km round-trip is perfect in an urban area.
With that distance, I get one hour of exercise per day and get to see a fair bit of the city (markets/festivals) and get to do fresh grocery shopping every day.
In addition, 12.5km per direction runs about 30-35mins with red lights, meaning that it's not more time consuming than public transport. The subway takes 22 minutes and I usually wait 5 mins at the beginning of the journey for the correct subway to show up and walk 3 mins on either end from the door to the platform and the platform to the office, and vice versa.
Also, I assume that I burn roughly 500kcal/day, which is quite nice and not too excessive.
I wouldn't want a longer commute. In Stockholm, it was shorter, from Fridhemsplan to Frescati is roughly 5km, but I'd make more stops for shopping, so it was similar in time.
Who wants to spend more than 45mins going to and 45 mins from work (with shopping every day)?
Last edited by acidfast7; 01-15-13 at 09:57 AM.