The Dakar Rally enduro bike winner in 2007, '09 and '10.
Main wikipedia article: KTM 690 Enduro.
This is a big, powerful single cylinder motorcycle. If you're not used to what that means, you should test drive some... mind you, having driven a 250 or even a 400 is nothing like this...
It's a very capable dirt bike and can be turned into a world crossing adventure motorcycle with some moneys.
Interesting forum topics to read:
More interesting stuff about the 690:
Throttle and stalling issues: www.monomaniacs.nl/tnt/KTM-690/Stalling-and-throttle-issues
For a much cooler than the stock hot exhaust, try a Wings pipe: www.youtube.com/watch?v=OqJc1pFE3jk and advrider.com/forums/showpost.php?p=16811330&postcount=38
Big fuel pump discusison: www.advrider.com/forums/showthread.php?t=641042 including after-market reviews - there is a 150$ pump available.
DIY valve check and shock service: www.advrider.com/forums/showthread.php?t=708813
Throttle jerkiness can be calmed with a G2 throttle cam: http://www.g2ergo.com/ very interesting system.