Does your car has the 722.6 5-speed Electronic Transmission??? If so, get it serviced ASAP before it blows up (especially if it had the factory specified 100,000 miles Service interval)!!! Forget it if you have a manual Tranny, lucky you!
I think as said its all going to depend on when and what was done last time, minimum is oil and filter, air filter, pollen filter, maybe fuel filter, maybe gearbox diff oil.
Its got full MB dealership service history when I bought it in 2005. From 2005 to date - car been serviced on time by an independent mercedes specialist. I dont have any major problems so far with the car.