on or off-road? remote or not?
if you're going to do a lot of remote off-road, the XR6 is a good enough starting point assuming you can get hold of the 40+ litre tank and have the time, money and knowledge to set it up. having had both 650L and 650R, I'd consider the 600R BECAUSE its not reliant on an electric start and, I'm told, it is gruntier than the L which is asthmatic.
if you're sticking to the bigger, tarred routes then you don't really need an enduro and you might as well go for a more comfortable seat :-)