Any rear wheel drive car with enough power and torque. There's plenty of threads in the GT5 Drifting Forum that will help you get started with drifting.
There will be different suggestions for a first drift car, but like I said, any RWD car is fine. Mazda RX-7s, Mazda Miatas, Nissan Silvias, etc are all good first cars. Don't take the easy route with 4WD cars like Mitsubishi EVOs, Subaru Imprezas, and Nissan Skylines.
Don't take the easy route with 4WD cars like Mitsubishi EVOs, Subaru Imprezas, and Nissan Skylines.