I've gone the multiple-choice route. I normally wear full-fingered out of habit from too many tasks done in gloves. My summer ones are fairly light, and suitable down to about 50 degrees. I have a pair of lightly insulated gloves that work down to the upper 30s, and I have some old PI Lobster Mitts that are pretty good to the 20s. All of these go up a bit in the wet, though the lobster mitts have to get pretty wet before I notice. I've sometimes considered adding a waterproof overshell glove, or if it were to be colder, some bar mitts.

I also needed something to keep my toes warm. My shoes have nice ventilation holes, that let cold air straight in and collect water. I have neoprene toe covers that are great for cold, and overshoes that do a pretty good job if I know it's going to be wet.