What are the best places to go backpacking/camping in Ontario?

That depends on a few things - how long are you looking to be out for? What kind of scenery are you after? What's your skill and experience level? Generally speaking, Ontario's provincial park system is an excellent resource for backcountry camping. The Western Uplands trail system in Algonquin Provincial Park is a good general recommendation, it can be adapted to various lengths (32-88 km), work as a loop or a linear trail, and in my experience is well signed and maintained. For more spectacular scenery, something on Georgian Bay or Lake Superior (ie in and around Killarney PP, Pukaskwa NP, Lake Superior PP, Sleeping Giant PP) could be a good recommendation, but again it depends on your level of experience (and how far you're willing to travel to get there!) There are also smaller parks further south (most notably Frontenac) that offer great experiences for shorter trips.

If you are planning a camping trip in Ontario and if you wish to move across Ireland, the scenic http://www.beechgrovecaravanandcamping.net/killarney-camping-kerry/. This small town of Ireland attracts thousands of campers every year, and for good reason. It has a perfect natural beauty along with modern amenities. It has a wide range of accommodation options as well as proximity to the city is well and good.