Probably a 2 flute 1/8 for the wood… maybe a downccut for the first pass if you’re worried about the finish. What all do you want to do? I wound up with some ball nose and v-bits after a little while. If carving or engraving is in your future, might as well get a couple of those too. Oh, maybe something bigger for surfacing your board if that’s an issue.
I can’t say much about the aluminum, as I haven’t tried to cut any. Probably a single flute, especially if you can’t control the RPM on your spindle.