Loads of choice from the MTB world, I have some casual looking cycling trousers from Altura, Castelli and Nukeproof. They're all fine, look a bit like cycling kit, but not glaringly so. Of the three, the Nukeproofs are my favorite, really thin and stretchy so I thought they'd wear out quickly, but are lasting well, not very warm though. The Altura are Ok, though the waistband is a little odd. The Castelli are a bit tight so I haven't worn them much, keep promising myself I'll lose enough weight for them to be a good fit...
I have some Endura chino type trousers, no better than other lightweight non cycling trousers in the same style, from the likes of Rohan and Craighoppers. Rohan Trogging are really comfortable on the bike, a slightly smarter type of joggers, they used to make a winter version, that I've forgotten the name off, but it seems to have disappeared from the website.
I might have agreed with the idea of just wearing civvies for cycling, but I seem to have gone the other way and don't own any cycle clothing that I'm not happy wearing off the bike in most situations.
