Have experience of running the following…
CK + Mavic 819's – rims nice and strong, tubeless works first time, but too narrow to give a good profile to bigger tyres (2.2" +). Also rims are quite heavy for the width.
CK + Stans Flows – rims a nice width, and seem pretty strong, give very good profile to tyres. Requires a rim strip to run tubeless, and are quite expensive. Built up nice and light with DT Super Comp spokes.
Roval Traversees – very light but pretty strong. Require a rim strip to run tubeless. Low spoke count means not as stiff as some, but a cracking wheelset.
Mavic Crossmax SX – great wheels. The '09 versions are very stiff, light, and strong. For me, the pick of the bunch, but expensive. The '08's can be had for quite a bit cheaper, and are also good wheels, but around 1/2lb heavier, and freehub design not as srong (so I've heard).