I would say Carlsen is slightly in the lead. Anand is right behind. Mostly because of his consistency, and by crushing Shirov in that match. Aronian next because of his consistency.
Maybe Nakamura, Gelfand and Kamsky are tied. {Boy I've watched a lot of chess this year!}
Carlsen won the Chess Oscar 2009 and 2010, but who will win it 2011? Kramnik had a great Dortmund but didn't impress in Wijk, Kazan, Amber and the Russian Superfinal. Carlsen won Bazna and Biel but had a worse Wijk, even if that too was a 2800+ performance. Anand did well in Wijk and Amber but without first places he won't win the Chess Oscar.
Nakamura won Wijk but has done badly since then. Gelfand won Kazan but without facing the top players, and the whole event was quite underwhelming. He had a bottom half Amber and all draws in the Russian team championship, and will probably need to win another event this year to be a serious contender.
The Oscar winner has usually been #1 on the rating list and if Carlsen stays first he might well win a third Chess Oscar in a row, especially if all his competitors have at most one good result during the year. At the moment only Kasparov, Karpov and Anand have more than three Oscars, while Fischer has exactly three. With a third of the year left my vote would go to Carlsen but much can still happen the last months of 2011.