We buy evaporated milk by the case. It stays fresh on the shelf and I use it in my coffee every morning. I use the whole milk variety as I find evaporated skim milk is very thin and grey.
In terms of cooking, I use evaporated milk all the time, basically instead of half and half which I often end up throwing away because I don't use it all up.
I use it instead of milk for a creamier mac-n-cheese (I usually use the white cheddar variety from Annie's or store brand 365.) I also use it for my white sauce and tuna noodle casserole (see January posts,) or if I want to add a little creaminess to a tomato sauce or my mashed potatoes. Just use a can opener and put a big slit on opposite ends of the can and pour!