If you want a pure depth or depth/stencil pbuffer, do NOT set the following flag:
// MAGIC: next flag caused the depth-only pbuffer to have RGB components?!?
as a parameter to wglChoosePixelFormatARB().
Also, do not use glview tool by realtech VR to list all pixel formats because it is bugged and incomplete. Instead use NV Pixel Format.
Hope someone finds this helpfull, I couldn’t find any mentions by searching the archives!