I concur with most of the above - go 8" or larger and buy appropriate for the need. Eastwood makes a nice 10" kit and it's good intermediate quality with two speed motor, 10" wheels and a pedestal- will probably last the average hobbyist user a lifetime - but they're proud of it (on sale for $340). EW Buff Motor 1HP 1750/3450RPM, Buff Kit & Pedesta

HF is cheap, but for occasional use it's fine. I buy buffing pads and compound at HF and it's fine.

Lot's of folks here have hinted at the safety aspect - believe them! I've been "wounded" several times from pieces slipping from my hands and launching at my being! I always wash my hands real well before starting, wear gloves and goggles, gloves cause stuff gets hot and goggles cause I need my eyes!

Regards All,
Glenn