I'm with Matt, if they still have thickness left and aren't too bad, I'll leave the rotors as is and try to do a good job seating/breaking in the pads.
Sometimes after you've driven on them for a while you can feel a pulse from warped rotors or poorly seated pads, and if that's the case, then I'll get new rotors, but more often than not, you'll be fine. Just my $.02 on my past experiences.

 

Just an observation here. When doing a brake job if you determine the rotors are at the low end of spec, say 30mm thickness, do replace them.

When I bought my car I noticed it had fresh brake pads all around. Good for me, right? Wrong! The previous owner had installed fresh pads but kept the old rotors because the were "in spec" as per the cast in Min. 30mm warning on the rotor edge. Well the measured thickness of those front rotors was right at 30mm and they warped the first time I got in heavy "stop and go" traffic. We call that heat soak.

If the rotors are stamped Min. 30mm, or whatever, and they measure even close to that 30mm then you replace them.

 

@tarhealcracker, that's just about what happened to me. Bear in mind that pads are about $150 for the fronts but the Jaguar rotors are astronomical if you have Brembo's. I bought aftermarket front set for $350, grooved and dimpled. The last owner just changed the pads. The disks had a lip of metal on both sides as well as edge and center that was about 1/16th of an inch. I don't think the rotors were ever changed.