In terms of divisional composition, I've always favoured 2Infantry, 1Artillery, 1Anti-Air. Had the exact same offensive and defensive attributes and gave good Air resistance too boot. Using this formula, I was able to get the computer to make all of the advances for me, instead of micro-managing, and win in both France, Yugoslavia, and Russia quite easily.
Plus, it allowed me to have way more divisions in every theatre. Playing as Germany, before I take the Danzig or war decision, I would have at least 2 army groups with 2 armies per army group on both the western and eastern fronts, and an extra army group with 1 army of 5 corps of mountain troops to the south and an extra 2 corps on the danish border.
By the time of the invasion of Russia I would have the same amount of infantry and up to 12 panzerkorps made. Invading Russia becomes a cake walk with that many troops blitzing the whole way to Stalingrad.