Did you say Ennis is the second greatest performance of the decade? Look I liked Ledger in Brokeback Mountain and consider it a good (albeit, overrated) film. But the "best" performance in the decade in which we've seen Lewis play Bill the Butcher, Paul Giamatti play play Miles in Sideways, Sean Penn and Tim Robbins both in Mystic River, Russell Crowe in both Gladiator and especially A Beautiful Mind (Oscar-bait, though it may be), Javier Bardem in No Country for Old Men, Bill Murray in Lost in Translation, Viggo Mortensen in Eastern Promises (an EXTREMELY underrated performance), Casey Affleck for The Assassination of Jesse James, etc. Johnny Depp has had several great performances alone.
Even just for the year 2005, we had Hoffman, who deserved the Oscar that year, as well as David Strathaim as Edward R. Murrow in Good Night, and Good Luck, who was also more deserving.
Look, I thought Ledger as Del Mar was very good, but I feel since his tragic death, his legend has grown higher than his actual work. And is nothing to do with the character. If you want to see an amazing performance of a complex gay man, watch Ian McKellan in the little seen Gods & Monsters. I'd also add McKellan as Gandalf to that list above.
Ledger was a really good actor. He was a leading man with actual great depth and tons of potential. And that potential can be glimpsed in Ned Kelly, Monster's Ball, Brokeback Mountain and The Dark Knight. But, unfortunately, he passed away. He could have been one of the greats, but I think the only performance he had that is on par with that list above is, to many critics' reluctant bemusement, the one where he had green hair and white make-up on. He was a good actor who might have been a legend, but now like James Dean, he is going to be sadly remembered for what he might have been instead of what he was, which was extraordinary enough.