Just under 10 miles each way. I have two routes that I take depending on the weather and which bike I ride. The routes overlap at the beginning and end and are approximately the same distance.
Route 1 is about 20% residential, 20% road (commuter arteries), and 60% trails, the trails being a mixture of pavement, concrete, gravel, and even wood! It goes through some parks in the city's beautiful river valley, and is quite peaceful in the morning.
Route 2 is about 20% residential, 40% road, and 40% trails. This is the route I do when I ride my road bike as it avoids all gravel. Not nearly as peaceful, but fast, fast, fast.
Both routes go through the river valley, so I have some decent climbs. Route 1 adds a ravine giving me an extra little climb.