As much as I like those Higgens boots, there is no way I would subject them to snow slush conditions as they will be ruined in no time. As already meantioned, leather soled boots are pretty poor in wet conditions so the minimum to go with is a rubber soled Leather. In one of the links provided by ElDub, they talk about "beater boots" and I think that's the approach I would take if I wanted to wear a leather boot.
Don't forget to factor in the cold either, both to your feet and your legs, meaning once the Fall arrives properly, I can't see you staying with chino's very long so your style is going to change anyway..Personally I would switch to each cords or moleskins trousers of the appropriate weight.
Getting back to the foot ware, the American solution is the duckboot such as the Sorrel or LLBean. Not very elegant, but very practical.
Personally, for wet/cold conditions I turn to "wellies" (not sure what you Yanks call them?) I am not talking about the cheap PVC boots kids have, but the proper natural rubber boots designed for the shooting/hunting market.
This version has the basic 2mm neoprene but they also do a version with a 5mm neoprene lining and extra foot bed insulation.
It common to see men wearing these (or other similar wellies) around town in winter and they usually change into decent shoes once they get to work ect…
I only mention them because the provided far more protection to the lower leg than a typical Duckboot design...