Treat your legs to some mountain clothing.  Most people spend a fortune on an expensive jacket and then forget they have a pair of pins sticking out from under that waistline draw cord!

I will start with the big 'no'. Don't wear denim on the hills. As outlined elsewhere, denim jeans have been a big causal factor in hypothermia and fatalities on the hills. In the 1980s and even now in some cases, knee-length breeches or peddle pushers were the legwear of choice for many people. Some people like tracksuits-type trousers and wind-proof polycotton trousers. Today there are umpteen styles of trousers from £10 to £150. Once more, cost doesn't correspond to technical application but of course materials such as those used by Paramo do cost a lot more.  Shop around, get advice and see what suits you.