Alex makes excellent rims in 28mm flavor. They're called FD28. They're 10-20g lighter than EX5.1Ds from DT and only $33 or so a pop. They don't have the $40 tubless rim strip option, though, like the 5.1s. Hopes are good hubs, so are XTs, it depends on how much you care about weight. DT makes great hubs as well. I guess Hadleys are too $$$? That's the most durable option.
Another rim you might want to consider is Tioga Factory DH rim. 35mm wide, 580g. I have it on my urban bike and these have taken royal abuse including getting jammed into stair and curb edges and are still straight. They're built super nice, with double eyelets and the bead is knurled so the tire doesnt' slip.
One last thing to consider is spokes, I would advise agains't too much butting (ie, tripple) and bladed spokes (ie CX rays or aerolites) as they reduce lateral stiffness of the wheel.
_MK
Another rim you might want to consider is Tioga Factory DH rim. 35mm wide, 580g. I have it on my urban bike and these have taken royal abuse including getting jammed into stair and curb edges and are still straight. They're built super nice, with double eyelets and the bead is knurled so the tire doesnt' slip.
One last thing to consider is spokes, I would advise agains't too much butting (ie, tripple) and bladed spokes (ie CX rays or aerolites) as they reduce lateral stiffness of the wheel.
_MK