Is the display calibration in windows 7 a substitute for Spyder or similar products? Or is it similar to the Adobe gamma utility, pretty useless?
The so-called calibration without a measuring device allows for full use of the possible monitor gamut under normal conditions. No more. It will never guarantee some sort of wysiwyg. So - pretty useless.
If you want a color managed workflow there is no way to go around a measuring device.
I myself use Windows 7 64bit Ultimate and a DTP94 with an Eizo CG 243 W Monitor,
which is a great combo and gave me a quantum leap in image processing.
But the biggest leap was not the awesome cool Monitor, but the measuring cell and the software
which was delivered with it.