When I got Irmo, I tried to do the same thing, only to find out that the display won’t work after the resume. At that time, it didn’t hit me that could be, actually, the display driver getting nuts; the only thing I thought was “software suspend don’t work on this machine”.
Yesterday, for a complete unrelated reason, I disabled the NVidia driver and switched back to the free X.org driver. This morning, I decided to try hibernate again, just to find out it works flawlessly.
Just to add more proof that the NVidia drivers suck, my old machine at work used to crash every time I left X and returned to it, so I couldn’t logout and loging again using gdm or switch to a console and later return to X.
I don’t run anything that used OpenGL or 3D stuff (maybe some xscreensaver modules, but nothing more), so I really don’t need it. No more tainting my kernel. And I can use my computer without a problem. Maybe, when NVidia decides to really open their driver, I’ll use it again; till there, I’ll stick to the unbuggy open-source driver, thank you very much.