Whew! Until now I seriously didn't realize how damn diverse WWII was vehicle wise:
http://koti.mbnet.fi/peksoft/files/wwii_units.htm
Not really sure about the Hungarian tanks though. Also, the French department looks (for understandable reasons) very slim.
As for the various units & their purpose:
Infantry: Cheap, good in cities
Arty: Bombardment
Mobile Arty: Faster, more expensive Arty
Submarine: Good vs big ships, hidden
Destroyer: Good vs subs, cheap, fast
Cruiser: Cheaper & faster than the BB
Battleship: Good vs ships, bad vs subs & aircraft
Carrier: Aircraft Carrier
Light Tank: Early in the game the only tanks available, good vs Inf, fast (usually)
Med Tank: Good all-rounder, most cost-effective tank
Support Tank: Good vs Infantry, slow, expensive, heavily armoured
Heavy Tank: slow, expensive, heavily armoured, good vs tanks
Main Battle Tank: Fast & strong all-rounder
Tank Buster: Cheap, weak but has a big +% vs tanks
Fighter: +% vs air units
Interceptor: +% vs bombers, usually better at ground attack
Jet Fighter: Can evade interception better
Strike Bomber: No collateral, but can kill units
Med Bomber: Good collateral, cheap
Heavy Bomber: Long range, big collateral, low max damage per unit
Jet Bomber: Can evade interception better
In paper>rock>scissors terms:
Tank Buster>Heavy Tank>Med Tank>Light Tank>Infantry>Tank Buster
Battleship>Cruiser>Destroyer
Submarine>Cruiser & Battleship
Aircraft>Battleship
Fighter>Interceptor>Bomber>Land & Sea Units
First version will include the new units, civics, and other graphic & text changes. Then comes the Spanish Civil War & Smaller Map.