Nevgal 2.35 stick-e, Stan's!
Another vote for the Nevegal! It's been my favorite rear tire since they first came out a couple years ago. I spent hundreds of $$ on tires in 2004 and 2005, looking for something better, or something that works as good but lasts longer, and always come back to the Nevegal Stick-E rear. As Dirdir comments, they are a bit washy in the front at speed, so I run a Maxxis Mobster (2.5 40a) up front, but this is a heavy FR tire, not so much an XC deal.
I have UST rims and run standard (non-ust) tires with Stans and no rim strip. My wife runs standard rims with Stan's and rim strip, of course. Neither of us has had a flat in over two years. In fact, I can't recall anyone in our group having a flat since switching to tubeless. I've worn out several tires with this setup and other than one "burp" on a newly mounted tire, have never had any problems. Tubeless is the only way I'll ever go!
Great example: last spring we were exploring remote state trust land near Tucson and got into some downed cholla. We each had several cholla branches stuck in both of our tires, going round and round through our forks and frames for miles (you don't touch cholla, so they stayed in until we got to pliers) - we rode for hours with them in there! Easily there had to be five dozen punctures in each of our tires, but none of the four seemed to lose any pressure at all, let alone go flat! In fact, my wife is still riding one of those tires!
Points to consider for your referance:
1) I live North of Phoenix, so my "home" rock is sandstone, basalt and a bit of limestone - slightly different from the decomposing granite / lava of the valley.
2) I'm on a 6"x7" 38lb bike and typically hammer apropriately for such a rig - hard up and hard down through tons of rocks rocks rocks, always trying desperately to keep up with these crazy DH/FR guys who all used to be XC pros and climb like mad too... Thus, my tire choice is biased toward the heavy / tough end of the spectrum. This is my one and only bike, though, and I do use it for everything - from swoopy Fruita-ish singletrack to ski resort DH to steep uphill fireroad training runs. If SoMo were in my back yard, I'd likely use the same setup, but if I were riding the less intense trails in the valley, I'd certainly go with a lighter tire up front - possibly another Nevegal???