I probably need this like a hole in the head but anyway here it is . . . a very clean used 2008 Kawasaki KLX450R.
I was debating between this bike and a 2011 KX450R which is a full on fuel injected motocross bike. The KLX is three years older for $2K less. When I test rode them, I immediately stood the KX up on end.
The KLX has almost as much power but it doesn't hit as hard. It is carburated and has an FMF pipe and factory headlight and taillight. For this reason, Kawasaki put a slightly stronger electrical system on the KLX . . . and it has an electric start too. I may look into making it street legal for getting from trailhead to trailhead but I'll wait on this. The KLX is often referred to as an enduro bike. If I really enjoy it I may take it a step further and either get a KX450R or a KTM enduro with all the DOT stuff already on it.
Of course, now I have the fun of spending many hundreds of $$$ on safety gear, boots etc.