It would make no sense at all to omit any of McGrath and Gillespie - who are proven class - or Kasprowicz, who's in excellent form in his International rebirth. It would also make no sense to pick Hauritz or White, who'll get mullered, and Lehmann/Katich is quite enough reserve twirly option.
If India were to play three spinners, it would mean that either they would require two seamers - and hence Patel, Pathan and Agarkar at six, seven and eight - which is exceptionally weak, or one seamer and Ganguly to open the bowling - which if it's as raging a bunsen as reports suggest, may not be such a bad idea as he's only going to need five or six overs. The other call is the 2/2 attack - Kumble, Harbhajan, Pathan and Agarkar/Zaheer (I'd tilt towards Agarkar for his record against the Aussies), with Sehwag and Yuvraj providing spin cover.
I would tend towards the three spinners/one seamer approach.