VW's 2.0 TDI does use a "Toothed" timing belt. Timing belts, because of their light weight and flexibility are easier on the engine components they are designed to power and cause less failures.
I, probably like you, would opt for a chain rather than a belt on a petrol engine, but not on an efficient diesel engine. Timing chains are best left to larger (V6 and above) engines and engines made for industrial use, where longevity is more desirable than efficiency.
I recently (Jun 07) terminated a lease with VW in Wiesbaden, Germany. I had the car for a year and used it to drive from Darmstadt to my workplace in Wiesbaden each day. I specifically chose a Golf 2.0 TDI, because (it's well known in Europe) VW diesels are bullet proof and extremely efficient.
I always drove between 160 and 180KPH (100-110MPH) and never had (or heard of) a mechanical failure. I did have two problems with the sunroof (electrical) and one with the passenger outside mirror heater (electrical). Both were covered by warranty.