Lots of good ones up here already, so heres a little more food for thought.
Road of Bones, in eastern Russia. Google it for pics. I know a guy who worked out there for a while. His pictures of the "road" and stories of craziness are pretty cool.
Would like to go back to Newfoundland and Labrador, the interior is pretty much wilderness. Very similar terrain to the territories. More moose per square KM then people.
There are some nice spots in Ontario, fall would be the time to see the trees changing colours in the south. Backwoods fishing up north is awesome.
Haven't touched the arctic circle, or driven an ice road yet.
South America has its attractions. Haven't wheeled jungle yet. A journey to the southern tip, anyone?
I'd go back to Alaska in a heartbeat.
Canol road should be honestly deserving of the word "epic". The north country has a dangerous beauty all its own. Ive driven some the southern portion maintained as a highway. The distances are vast, the terrain often brutal. It will be a worthy challenge. But based on the people I've met so far, this is the group for the job.
Austrailia definitely makes the list. I work with a guy from down under, sounds like a blast.
Cape town to Cairo. As long as you can dodge the political crazies, malaria, and all the things that can eat you it would be an eye opener I'm sure.