1.Clarke
2.Cosgrove/Rogers
3.Hughes
4.Khawaja
5.Bailey
6.Warner
Clarke obviously is the undisputed #1, my pick as the #2 batsman in Australia atm is Cosgrove, because of the stupid selectors he might never play for Australia but he is gun player, for me he's probably one of the best players of spin too, in a ideal world he would be playing for Australia but that isn't the case and in such a scenario if he is not a valid option then Rogers would be my pick, he is surely nowhere near as gifted a player as Cossie, but he is gritty batsman who just finds a way to score runs in most situations which would be invaluable for Australia.
Hughes atm is #3, he has got a few loose ends in his game but he has the talent to overcome those obstacles and moving forward he would be big player for Australia. As for Khawaja, was reluctant to name him in this list but then again he's an amazing talent and AFAIC, him fixing his attitude is pretty much the only thing standing between him and a permanent place in the Australian side.
My 5th pick is Bailey, his shield form hasn't been great this season but he is player of great class, his biggest strength for me is his ability to score runs in tough situations, he is no Mr.Cricket but he for me has the ability to play the role of the 'crisis man' in the current Australian side which was something Mike Hussey did so well over the years.
Anyways... 12 months ago Warner would probably have been 3rd on my list, unfortunately his temperament has been seriously exposed since then, he probably thinks he has already made it big and he probably takes his place for granted and if he doesn't snap out of this, then he would fall way behind in the pecking order.
Honorable mentions: Wade, Dave Hussey, Voges and Burns.