Personally, I like 500K pots with any kind of dual-coil pickup, but I use a 0.022 uF cap for the bridge and a 0.015 uF cap for the neck. My reasoning is that, with the lower value cap, the neck pickup loses less treble ... and I prefer that, since it tends to be the "muddier" pickup, in my experience.
I've heard proponents of 1 MegOhm pots with humbuckers, but using 0.047 uF capacitors (or higher), but those people are not the norm. I've yet to try it, but the increased range of resistance to sweep across the frequency range of a pickup makes me interested to try it, as an experiment. I think the conventional wisdom is that the higher value potentiometers preserve more of the higher frequencies across the sweep between 10 and 0.
Typically, lower value pots with higher value caps = the least amount of treble. So, 500 kOhms with 0.022 uF is right in the middle.
Edit: The scientific sticklers will probably point out the holes in my assumptions and may inform you of the proper nomenclature and actual aural phenomena.