Hmm. …
I’m leaning towards the U.S.A.
Possibilities:
→ Sierra High Route, California
→ Continental Divide Trail – Indian Peaks Wilderness to the South San Juan Wilderness, Colorado
→ Lake Tahoe Rim Trail, California
→ Wonderland Trail, Washington
→ Enchantment Traverse, Washington (friends loved this area, hiking it this past summer)
→ Chinese Wall, Montana
→ Maroon Bells Loop, Colorado
Comments?
The toughest option there is the High Route. Route finding. Off-trail. Scrambles. Snow. Bugs. And no protection from the sun.
I’d try to duplicate the trip undertaken by the world’s greatest hiker, Andrew Skurka.
his trip report – Sierra High Route — July 2008
… Leave a comment if you’ve an opinion on the best hike of these listed. Or any other in the continental USA.
besthike.com 
I would say the place to be next year is in Oz. There are many great hiking opportunities in all states. The ones I know best are in the Victorian Alps and along the Great North Walk between Sydney and Newcastle in NSW.
Ha. Thanks for the tip. … But I’d rather hike in Australia during the North American winter. It’s snowing in my town right now.
Depends which part of Australia. Alps and Tasmania during our summer (northern winter), but in the north, for example Kakadu or Hinchinbrook Island our winter is the usual option, although Kakadu in summer apparently is good but rather wet and humid. Spring is a good option for Western Australia and around Sydney.
Absolutely Wonderland or the Enchantments if you choose US. Both are excellent choices. Given the two, I’d rather hit the Wonderland trail. Check out trip reports from wta.org for either Washington choice to see what is happening when on the trails.
I’m very partial towards anything in the Sierra’s, but that route of your friends sounds interesting too.
DSD 🙂