Previously unreported amorphous carbon and nanocrystalline diamond films have been prepared by microwave plasma-enhanced chemical vapour deposition (MPCVD) in two novel reactor designs. Ar-CH4 gas mixtures were used in a 1 kW coaxial bladed reactor design, and Ar-H-2-CH4 gas mixtures were used in a 6 kW reactor with a dual mode applicator. Films were examined by ultra-violet and visible Raman spectroscopy, and subjected to nanotribological investigation by scanning force microscopy (SFM). The results are compared with those from randomly orientated and (100) microcrystalline MPCVD diamond, pulsed laser deposited (PLD) and filtered cathode vacuum arc (FCVA) carbon films, Si wafer and electroformed Ni. A consideration of the relative merits of the various film types for microelectromechanical systems (MEMS) is presented.