1) Heinz Guderian -- For his, at the time, rich new insights on armored warfare. For his part in Operation Barbarossa. For the fact that he poised to launch the final assault on Moscow when he was ordered to turn south towards Kiev, not his fault.
2) Erich von Manstein -- Invasion of France
3) George S. Patton -- A cult hero. But for me he still was one of the best the Allies had (the German commanders knew this). His image didn't work in his favor, but he was a strategic genius in my eyes. His part of turning the tide at the Battle of the Bulge shows this in my eyes. Had they listened to Patton instead of Montgomery, I believe the war would've ended much earlier than it did. Montgomery's Operation Market Garden was in my eyes a large failure, considering they did not take Arnhem and had massive losses. Patton wanted to push into Germany, but instead they went for Montgomery's bold plan.
4) Gerd von Rundstedt -- Not the one with the genius plans, but he was a very steady commander during the war and deserves far more credit than he got. Always did his best for the Wehrmacht, even though he was not a fan of Hitler. Only until D-Day did he get massive losses, and again, not his fault. The war was already lost for Germany by 1944 in my opinion.
5) Albert Kesselring -- Holding out far longer than expected against all odds in Italy against the Allies in 1945.
Honourable mention: Omar Bradley -- Without Bradley there would be no Patton the way he was and vice versa, I believe they complemented each other very well with their difference in personality and views.