I'm definitely going the knobbier route next time around. The Gripsters are great on the road but I can see how they got the nickname "Slipsters" when you take them on loose surfaces... Only catch with me is I use my KLR to commute mostly so the miles are pretty much all pavement with a little bit of gravel roads and such sprinkled in. Not sure if I will just go for something like a Mefo Explorerer or a more aggressive tire next time around. It's hard to shop tires because there are so many different kinds with different attributes. Would be neat to try a set of those Trakmasters, bet they howl like a bugger on the highway?
P.S. That looks like one sweet trail your riding! Everything here is flat, blech!