wildcat

That's about the size of it. More spokes make a slightly heavier wheel (~35 g for every four spokes), but it's stronger since there's less rim distance between spokes. Also, since power transfer takes place through the spokes on the rear wheel, more spokes mean each individual spoke has less stress put on it. Your weight is a factor, too, since fewer spokes translates into less load capacity per wheel. Basically, unless you have a specific reason to do otherwise, 36 spokes are generally just fine.

Now that said, my wheels are 28 spoke, mostly because I found rims at a reasonable price that just happened to be 28 hole. I haven't experienced any problems, but the bike isn't really out of its break-in period, so time will tell. Besides, I think the mechanic that put them together will probably affect the durability at least as much, if not more (he's a total n00b at this, but he's learning ). I suppose if you have your heart set on 28 hole and you're not particularly heavy, they'll be OK.

As for Hope hubs, my friend has a set on his mountain bike, and he loves them. In the few miles I rode it, they seemed to be nice units (although his rear is a LOT louder than my Ultegra 9sp, but that might be due to wear/maintenance, being that they're a couple years old).