Welcome to the forum Pathfinder,
For unpainted metal WWII, I'd back up what Alex said, the ONWTC figures are very good, very little cleaning up required and minimal assembly.
For plastic, I'd suggest Conte or TSSD. Conte have US Airborne, British Airborne and German Wehrmacht and SS sets in soft plastic, and US GIs (27 poses) in hard plastic. Some of the Conte GIs and the ONWTC metal figures are the same.
TSSD do Winter Germans, Russian Infantry and US Infantry / Weapons support, as well as US Marines and Japanese Infantry.
Hope that helps,
Simon