Anyone using studded bike tires on a commuter in milder climates?
Studded tires don't help on snow any more than knobbies do - they're for ice. The canonical website on winter biking is probably IceBike. 

It really depends on how far you want to go - a wide MTB tire at low pressure is nice in the snow. The aggressive studded tires are designed for riding in snow, not mostly cleared roads with possible bits of ice. If you're riding on plowed roads, a beater bike (since road salt does wonders for ruining your drivetrain) with some mild studded tires designed for commuters (e.g. Schwalbe Marathon Winter) are a good way to go (though many people get by without studs for winter as well - they're additional safety when you hit ice; I've done several mid-west winters without studded tires). If you're not going on plowed roads, get something aggressive (but note that if the roads are clear, you'll wear down the studs excessively and have excess resistance). 

As for keeping the fenders on, you might not want to do that since they help pack and accumulate snow. I like to use a downtube board and a clip on tail fender (SKS X-board and X-tra dry) since they don't make snow accumulate.