I like this topic!
In my (limited) experience, many easily available stockings tend to be more sheer, and hence, more easily run. More expensive doesn't necessarily mean run-proof! I shopped around until I found a brand that makes stockings in Tall sizes. I think it helps, along with *not* buying a very sheer stocking--at least if you want them to last for more than one wearing!
I also don't think the "hold-ups" ever stay up. Just my opinion, but it's really annoying if you're walking around and one of your stockings either rolls down or sags. Ugh!
(Besides...I always wonder who notices the garter straps under the skirt in my suit! I always do my part to keep the meetings from being dull!)