Just curious as to what people think are the best shouts for a mage to use?

Disarm is good. Many melee based enemies that come at you with an axe, you can disarm them easily, and they have no way to fight back.

Slow Time. It's great when you need to cast Master level spells.

Fire breath, Ice form, or something like that
It might suit well.

unrelenting force. ice form is good for stopping them while still harming them. become ethereal is especially good if you're in a hot spot and need to get out quick(even if its jumping off a high ledge, done that a few times), even better if you meditate on it, you get a health regen bonus while ethereal.