Malorganite will keep deer away from plants...not sure about the rabbits. Put around outside of plants or if you can around the perimeter of your yard. Do this once a month, and redo if you get heavy rain.The smell will keep them away.
Scent based repellents like Milorganite will work for awhile, until the deer get acclimated or get hungry enough, but basically planting hosta is like planting a salad bar for deer. In the long term, your only hope is to put up a deer fence, or consign yourself to not having hosta.
In Texas we use orange peels or anything that has citrus smell and plant lemongrass also.
It sounds crazy, but you can take human hair (get it from your hairdresser after a haircut) and put it inside of knee-high pantyhose, tie and hang it nearby. Supposedly it causes the deer to smell a human and helps keep them away.
Also, I have one of these Scarecrow Sprinklers and as long as you remember to turn it back on after working in the yard, it works GREAT! http://www.contech-inc.com/products/home-and-garden-products/animal-repellents/scarecrow-motion-activated-animal-deterrent (It's much cheaper than MSRP on Amazon or eBay.)