The right start:
Jaffer's sealed his place in the team as a frontline opener, having had success against bowling attacks getting stronger with every series. His feats against a bowling attack with Shoaib Akhtar make him a serious contender. However, the bowlers in Australia (who don't get injured so often, so soon) and also the flat, hard pitches there are a totally different story, and he may stick out not so much for technique as lack of urgency, compared to the rapid, rollicking starts by Aussie openers.
Of all the available options, he and Sehwag are the best bets man for man, but a no-show when together. Never have they had good starts together. Hopefully that will reverse here. With Sehwag, the on-his-day factor puts him way ahead of the rest. Wicketkeepers cannot open, and a dreadful series against an Akhtar-led Pakistan team proves that. If Karthik can't score against Akhtar and Arafat in India, how can he score against Lee, Mitch and Tait abroad? He's no better than Irfan Pathan, more a wicket-taking pick than a run-scorer. Even Gilchrist, the legendary wicketkeeper-batsman, doesn't open a Test innings!
Rahul Dravid opening is dreadful- he's in dreadful form, he's a crucial player and the opening slot is crucial. Tendulkar to open would free up a middle-order slot, and is worth a try, when he's opened for over a decade, even if it is ODI cricket. Yuvraj at the top is a gamble, and consequences of failure are disastrous. So that would leave us with Jaffer and Sehwag to open. If not too confident, open with Tendulkar, and if not confident at all, open with Irfan. The last two options leave you with a place for Yuvraj, which is obviously not at the top.