I'm fine with my MTB shoes and REI hiking socks down to about 20F. Below that I wear my KEEN "Austin" cleat-friendly casual shoes. They are like lowtop hiking boots and offer plenty of warmth in any temperature I'm likely to encounter (we rarely get below -10 in the high desert valleys of the Western Rockies). Below that, our Canadian and northern Plains compadres would have the skinny.

Well done on your first chilly weather commute. As spring comes 'round you'll know why 30F is "chilly" and not "cold"

Also - when the temps drop below 20F I wear large coverage clear safety glasses ($6 at hardware stores) in lieu of my Scott cycling glasses - better coverage to keep the eyes and cheeks shielded from direct wind.

Finally, since you're in New Jersey, it is worth considering some studded tires for the deep winter months. I ride the Nokian W108 and love them. I feel better on my bike than in my car on black ice days.