I'm in the market for a pair of versatile black pants that can be machine washed AND will keep their color, so something like a cotton chino or jean is out.

I used to wear black tropical wool pants to work regularly, but I don't want to go down the "dry clean only" route.

I'd prefer a straight leg, trouser style, but a good, thick legging that can be tucked into boots is good too. Any suggestions?