Keep stock of vanilla? Obviously yes. It's kind of expensive, but it lasts forever and makes everything more awesome.
Speaking of awesome, and vanilla...
My favorite way to make hot chocolate:
Over a double broiler (basically just a metal or glass bowl over a pan of simmering water... DO NOT let the water touch the bowl), slowly melt chocolate of your choosing. I like to use the least sweet Ghiradelli chips; they're cheap and good, but would use better if I could afford it. Warm up milk in the microwave (or 2/3 milk, 1/3 cream like I like to), and mix it in the chocolate until it reaches the desired consistency. Finish it off with a dash of vanilla.

