I find that the Gretag Macbeth Eye-One display produces superior profiles compared to the Colorvision Spyder. Another alternative worth considering is the BasICColor Display bundled with the Squid monitor sensor.
The major limitation of the PhotoCal software is that the instrument is not used to measure the black and white levels (you are basically eyeballing it), which produces less accurate profiles.
There's more information on hardware calibration at
Dry Creek Photo.