Re: Which Nadalīs slam would you rank highest?
I think this has been done (at least several times).
My take on what you listed-
Obviously RG 2005 is the most important one. Set his confidence. The rest of his RG titles didn't really have anything to interesting to discuss.
AO 2009 was his most impressive slam. Only slam event where he was actually dominating with his backhand consistently. Too strong mentally when it mattered most.
I don't really view Wimbledon 2008 as great as many others. Sure, a lot of drama, but it was a chokefest. Federer had plenty of chances in the first two sets and blew them, while Nadal had plenty of chances in the 3rd and 4th sets and blew them. Then Federer again had plenty of chances in the 5th to go up a break, but failed to do so. Neither of them really played their best. Just happened to be the case where the scoreline stayed even.
US 2010 was similarly nothing special. He played solid in the final, but he got there with minimal effort. Benefited from a very good draw for himself.
Wimbledon 2010 is something I would put up there with AO 2009. Great tennis throughout especially mentally, although I still despise some of the "tactics" used against Philipp. Final was pretty boring, as Berdych, who I thought would end up being a consistent challenge to Nadal, failed to do anything special just like all their other matches since 2006. Pathetic.
Federer / Haas / Safin / Gaudio / Kuerten / Youzhny / Nadal / Gonzalez / Ljubicic / Hewitt / Soderling / Wawrinka / Coria / Nalbandian / Kohlschreiber