The best MPC for you is going to be the one that does what you need it to. I've used them all from the MPC60 to the REN, and they all served their purpose as I needed them. My favorites by far are the MPC3000, MPC2000xl, MPC1000, MPC2500, and MPC Renaissance.
But I agree with B-Cool, the MPC REN would be the best way to go in this day and age. Digital control meats pumping analog sound. It's awesome.