High rollers are a good all round chouce. I run Bonty Big Earl's on mine (2.5 but come up smaller), not too heavy, lots of grip on most surfaces, bit light in the sidewall but makes them roll fast.
Oh and I heard terrible things about DT5.1s and tyre fittings but never had a problem with either spesh enduro's (now discountinued shame) or the Bonty's
NN's are great tyres, but never got on with the 2.4 at all.
Chris/Mick couldn't make tonight but hoping to be there on Sunday. Have dug out mud tyres and been loading up all my old pictures of the Chilterns to get me in the mood!
We were getting snowed on the top (near the worc beacon) a few weeks ago. Gale force winds driving snow sideways into your face, and make the lights just reflect back. The descents were quite interesting... It'd be magical up there with a good lump of settled snow.