I love my .17 HMR firearms.
For a rimfire rifle there is a lot of power there. There is a tremendous amount of energy behind the little 17 grain V-max. It will knock squirrels dead out to at least 120 yards, which is about as far as I have tried to shoot it.
If you would like some examples of what it does to tree squirrels at distances from 20-70 yards I would be willing to post them. I have seen limbs torn off and tossed 8 feet away, blown holes big enough to see sunlight through, gaping wound cavities.
For deer the .17 HMR is probably not legally ok, nor is it an ethical choice. If I had no other option, and was starving. I think a hollow point right behind the ear would drop a deer. I wouldn't want to test this theory though.
For a coyote, yea I intend to try and kill a coyote with my .17 HMR at some point. I feel competent enough with it to do it. The accuracy on these rifles is pretty outstanding.
The .17 hmr will have no problem killing animals as small as chipmunks (if the shooter can shoot a chipmunk) or as large as coyote with proper shot placement.
I have taken 1 squirrel with my Taurus .17 HMR revolver using v-max rounds. Distance was probably about 25 feet. Squirrel fell over where he stood.
If you can wait for it, check out the .17 WSM. It will have a lot more umph.