How do people dust their systems?

Only if you don't use a vaccuum!
I use a product called "Grab-it" it is a finely woven paper cloth that I tame down with my Zero-stat gun.

Interesting - maybe I do have a problem! Anyway, I use a feather duster, if I add a new item I pick everything up while I'm back there and "lemon pledge" the rack itself.
I don't add things often.

There are some new hi-tech cloths (one I have is made by 3M) that pick up and hold dust very, very well. They (supposedly) hold dust in the interior of the weave so you're not rubbing the dust onto the surface you're dusting. They're used dry and are safe for CRT screens and hence any equipment surface. Hanky-sized, probably $3 a piece.

Geez, we REALLY need to get a life. Sitting in front of the the monitor discussing the ways we dust our gear. But seriously, every week I just dust with a feather duster. (Also, Billy Baggs makes a nice wool duster - you can check it out on his web site.) Every few weeks, I use the round soft brush attachment on a vacuum to clean the areas that dusters don't reach. Will.

I try to maintain the illusion of clean. So long as you don't disturb the dust it's fine. But once you touch it, you have to clean everything.