I put new front brakes on my Tahoe this weekend, and found the rotors to be corroded onto the hubs. I saturated all joining surfaces with WD-40, beat on the things with extreme prejudice, pried on them with crowbars, and they would not budge. At all. I probably spent an hour on the darn thing. I seriously evaluated having to take apart the hub assembly to dismount the rotor.
Then I got online and found this trick that worked absolute magic, I was extremely impressed with how well this worked, and just have to spread the word and save some sanity of my fellow do-it-yourselfers.
Take two bolts, 1/2 inch was what I had laying around. Insert them into the holes where the calipers bolt to the hub. Thread the bolt through a nut that you sit between the rotor and the hub. Start tightening the bolt, securing the nut with a wrench, and work back and forth applying even pressure to the rotor. In the case of the rotor that had been worked on an hour before, this caused the rotor to pop right off, immediately. The second rotor came off with a sequence of tightening the bolts until I was concerned about stripping the nut, then loosening them, rotating the wheel, then tightening again. When the rotor had made almost one complete rotation doing this it popped clear. Took 10 minutes. Sanity achieved!
If you are reusing your rotors, then place something flat between the rotor and the bolts to protect the surface. If you are not, then crank away....
Anyway, here is a pic of my front wheel assembly to show you what the setup looked like - the bolts are extra long but are just what I had immediately at hand, and worked fine....
I made certain to apply some anti-squeal compound to the base of the hub and the edges where it contacts the inside of the rotor, hopefully to avert this problem from happening again.
Oh, and I put EBC rotors on with Greenstuff pads and am very pleased with the results.