I have a pair of the Rivendell MUSA pants. (I think I wrote a review somewhere, too.)

They are very comfortable to ride in! I wear them on my commute to work, wear them at work, wear them on the commute home.

For longer rides I've worn bike shorts under them.

I've also worn baggy cotton shorts over my bike shorts, and those were fine. And loose skorts.

I wear wool knit shirts when I ride. Plain ol' Ibex long sleeved t-shirts or t-necks. If it's really hot I wear a bra-top with a loose baggy long-sleeved nylon sunblock shirt over it. (made by Kokotat)

Works for me!