As we like to like to play tourist on our tours and visit places of interest it is quite nice to have some trousers to wear rather than just cycling shorts. Since we have been using our Brooks saddles we really have found that we don't really need to wear padded cycling shorts. We therefore now used zip off trousers to cycle in.
Due to them being zip-off they can very quickly be changed to shorts when it is warm. We are currently using a version made by Vaude which have a shaped seat so that there are less seams on the seat area to cause any problems and they have velcro tabs on the legs so that you can narrow the legs to stop them from getting caught in the chain. They are easy to wash and dry quickly.
Unfortunately Vaude seemed to have stopped making these zip-off trousers but I notice that Endura make a similar product the 'Hummvee Zip-off Trouser'.