Most professional mechanics solve this problem by first spraying with penetrating oil and then using an impact wrench against the rotor face to hammer between the studs. The continuous vibration helps the penetrating oil work in between the hub and the rotor and it comes off quite quickly.
Guys like you and me (sans air equipment) are left using lesser technologies. I have a very nice lead-head hammer and a 1/2-inch punch I use to bang between each stud. If I miss, the lead head won't damage the stud threads or anything else. Alternating between hammering between the studs and spraying, it usually works. Definitely concentrate on shooting the spray around where the studs penetrate the rotors. Banging on the inside face of the rotor will help, but be careful.
My first brake job ('95 Grand Cherokee with 2-piece pressed together front rotors) was the very worse. The rotors were made out of a cast ring (the braking surface) with a press-formed hub pushed into the casting - total junk! They were subsequently recalled when corrosion would get into the seam between the two and result in the hub becoming disconnected from the rotor surface (look Ma - no brakes) !!! On one side, I had to hammer a wooden wedge between the back of the rotor and the pitman arm until the rotor popped off. The other side, I just sprayed and beat on it for about four days (before and after work and at night) and it finally came off. Fortunately, my wife was away for the week and I didn't need the second car.
The lesson to be learned here is always put a light coating of anti-sieze or silicone brake lube on the face of the rotor that contacts the hub - including the inner rim of the rotor. The next guy to do a break job on the vehicle, whether he knows you or not, will realize that the last person to work on those brakes cared about doing it right rather than doing it quickly.
A brake job done right - anit-seize on the hub, silicone lube on the slide bolts, silicone lube on the back of the pads to prevent squeaking, and silicone lube on the spindle brackets where the pad ears ride - is something you will never see in a commercial garage. Another good thing to do, although it requires some coordination, is to open the caliper bleed nut as you use the c-clamp to back the caliper piston back into the cylinder. By doing so, you bleed out the fluid that's been sittting in the caliper cylinder (getting heated and/or dirty). Otherwise, as you push the piston back in, the dirty fluid gets pushed back into the master cylinder - usually overflowing it.