If you enjoy board wargames ..it's all of it.
I really get into all the different ways you can go .. truly epic in scale .. er ...altho ..it would be hard to conquer the world if you started with Ireland -grin- .. and yes, you can

I have yet to try anything other than Germany .. just tryin different ideas out .. some work, some dont.
Need infantry .. I build more than Hitler did, and more panzer divisions with more panzer brigades than he did.
Typical loadout I find works very well is 3 brigades of infantry, 1 of arty for an infantry division.
3 brigades of light tanks with one of motorized and later mechanized infantry for my panzer divisions.
..then.. when I get 5 brigade divisions researched ..I add a marine brigade to my infantry and another tank brigade to my panzers.
They get real mean.. just beat up on stuff

-GE aka Frank