Allow me to stick my vote in the ring - and not out of the need to give the Aussies a sympathy vote - I can see them winning this tournament.
ZOMG - why not India?? Well India are the defending champs, have a lot of experience and have a powerful batting team. But I think the bowling lineup is fairly weak compared to the other teams. I think the Indian pacemen will need friendly conditions to succeed as guys like RP Singh, Irfan Pathan, Zaheer and Praveen all need the ball moving to trouble batsmen. And even if the ball is moving, I'm not sure there is a proven consistent T20 legend in that group. Yes they perform here and there but too inconsistently, and maybe only RP Singh could be called a consistently good T20 bowler.
Australia does not have some super awesome bowling lineup by comparison, but I think I trust Mitch Johnson, Bracken, Hilfenhaus and Lee to get the job done more than the Indian quartet I mentioned before. Spin could be the difference between them as Harbhajan is quite an economical bowler and Hauritz for Australia probably can't match him in that area, but Hauritz is no mug and he's been a shorter form specialist for NSW for the last few years now, so he has the mindset to restrict runs.
Don't get me wrong, India are still one of the favourites for sure. But I'm just saying I don't think their bowling is that great. I'd much rather the Pakistan or Sri Lanka attack for example.
OK so I've raised my (pretty much only) doubt about India, but why Australia to win then? Well I think Australia has batting just as talented as India's

Symonds and Warner are proven demolition men - Symonds in particular has probably the best T20 record of any player. Watson and Dave Hussey are experienced, successful T20 players too. Ponting and Mike Hussey haven't dominated in T20 like other forms, but I wouldn't be dismissing their talent just yet either. All in all, Australia could put quite a formidable top 6 onto the park.
I think Australia's only negatives are experience and recent form. The experience weakness is a little overstated. After all, the Indians and South Africans are probably the most experienced squads, but they really haven't played a LOT more T20s than the Aussie guys. Everyone is still relatively inexperienced in this format.
And non-participation in the IPL has been a criticism for Australia too, to hone form and gain experience. But guys like Symonds and D.Hussey are there and using the IPL to discover touch and confidence. As well as Brett Lee who is looking to regain rhythm. But I think it was more important for some of the major players to rest and hopefully I'm proven right when Ponting, M.Hussey, Haddin, Mitch Johnson etc comeback to international cricket refreshed after their long summer in Aus and SA.
Of course, we'll see how it plays out, but I believe the Aussies have WAY too much quality and hunger in their squad to be written off so easily.
And my dark horse for the tournament: England.