Down to about 40F you need riding gear with a windbreaker layer, including pants, a full face helmet, something that covers your neck and good gloves.
I use split leather with "thinsolate" liner gloves from walmart (~$15) most often. I have a pair of HD winter gloves that I got a great deal on from the Goodwill store, but they are big and bulky, and the nylon outer shell does not give me a confident grip on the clutch or brake levers.
The best thing you can do is put a windshield on the bike.
I only ride up to about 45mph on my 1/2 hour commute, but Im comfortable with my gear.
If you get on the interstate and are going 75mph look at the windchill vs windspeed graphs -high speed winds strip the heat off any exposed skin and goes thru anything that 'breaths'. Thats a whole different ballgame.