It may be just me, but I hate walking in jeans, even in jeans that are loose fit--Like 569's. The primary reason I don't like them is that the fit in the seat and waist is just too tight for walking. Perhaps it is the way I choose to wear my jeans; I absolutely refuse to wear a pair that are baggy in the seat, because it makes you look like someone's grandpa. Looking good in loose fitting jeans is a hard look to pull off. And before you harsh me for appearance comments, You do have to consider that for many people, your appearance at work does matter. Body type matters too--If your are thin, you can get away with wearing loose fitting jeans. I'm overweight, so loose fitting jeans look like crap.
For walking, pleated pants are the way to go. They fit properly on the waist but still allow freedom of movement, especially in the upper leg and hip. Since slacks are meant to be worn looser than jeans, they don't look like crap when fitted properly. So I'll opt for RL khakis, or else hiking/convertible shorts. I have some from REI that are going on 5 years, and even with thigh rub there is no wear.
My round trip walk to and from work is 3 miles.