For my money he should have won for Catch Me If You Can and Django Unchained. The year he was nominated for Catch Me If You Can I don't remember the nominees but I still think it's his best performance/movie. Then to not even be nominated for Django was sort of a joke to me. Him and Sam L. Jackson were more memorable supporting characters then Waltz's to me. Wlatz did a fine job but we aren't going be talking about his character 15 years down the road like Leo's.
I looked up that year's nominees and he was up against Daniel Day-Lewis, Jack Nicholson, Michael Caine, Nicolas Cage, and Adrien Brody (who ended up winning for
The Pianist). I haven't watched
Catch Me If You Can in a long time so I remember next to nothing about it, let alone DiCaprio delivering his best performance. I think I preferred him in the same year's
Gangs of New York - while he was definitely overshadowed by Day-Lewis, the fact that he held his own against such a towering performance was still rather impressive. Unfortunately, I didn't think there was anything special about his
Django performance - it never felt convincing, it just felt like he was going through his usual bag of Serious Acting tricks (bright-eyed charmer, furrowed-brow angst, gritted-teeth anger, etc.) but with a deep-fried Southern accent sprinkled over the top to distinguish it. I only talk about it now to point out how fundamentally bland a character he played with all his heart but still couldn't pull off (perhaps a badly-written character more so than a badly-acted one?) That being said, I didn't think too much of Waltz either - he definitely earned the Oscar for playing a Bavarian rogue in
Basterds, but he more or less repeated that with his work in
Django so that second win felt far less deserved.