After I remote into my desktop machine the monitor will not sleep again until I use the desktop locally. This started several months ago. Hard to say what changed since I don't think I immediately noticed a problem.
When I first remote in the monitor will immediately wake up and display the "remote logged in from blah blah" and will go black after the configured sleep time, but is still powered on.
This is on an nvidia card and Vista SP1, though it started pre-SP1 and I've gone through a few video driver updates by now.