Ktm 950
I have one, and it rocks.
It's by far the best multi-purpose bike I have ever owned. Mine is the 2005.5 950 Adventure S. Carbs, higher suspension, etc. Lightly modified with Touratech bash plate, beefed up front suspension (SuperPlush), Zega 35 l hardbags, and some ergo stuff. Carbon tank protectors, and NO crash bars!
Perfect for long distance, although many complain about wind buffeting and a ****ty seat. I'm a manly man, and just suck it up. LOL. I'm just cheap.
Once at pavements end, the fun definitely begins. Depending on your skill level, it will go virtually anywhere. Challenging tracks are a huge pain, and it becomes hard, hard work. A 450, 525 would be fun, 640 Adv less so. But if your overlanding with equipment, any of bike is going to be weighted down with gear, and thus, not a lot of fun to do challenging dirt.
The big factor in the equation is how much time will be spent on the tarmac. For me, it is 2 1/2 hours to get to good riding (from San Francisco), and the ability to blast as fast as a want is a real asset. Even the road twisties are super fun (limited only by more off road oriented DS tires).
Fire roads and more open off road is where the bike really shines. Suspension is FANTASTIC, and there is unlimited power. You can really rip. Even with gear and at altitude. Huge grin factor.
I rode the GS1200 before going KTM. Nice, but tame. Two block on the 950 was enough for me to make my decision. It is a beast. I have a great high volume dealership--Scuderia West. That helps. Can't say enough good things about those guys.
Horrible range, and gas consumption. I'm lucky to get 40 mpg. 200 miles is a stretch. Lots of issues, but the performance is awesome. Hope this is helpful.