I commute with a set of Jandd panniers. I also have a Ortlieb pannier. I'd would even go so far as to say that they are the best pannier out there but also very spendy! Arkel Panniers are also good.

BUT for winter commuting hands down the very best is Oyster Bucket Panniers. Made by Cobbworks. http://www.cobbworks.com/

Have a look! They are super waterproof and very functional. And if you're handy you can make your own for cheap.

Ciao,
Timothy