Bailing out the Banks/Credit Markets was to prevent a 1929 Panic situation. Beyond that is kinda dodgy as Bailing out other Industry hasn't really been tried, though I suppose the Chryslet bailout in the '80's kinda applies. It seems to me though, that Bailing out Supply is more a continuation of Trickle Down(Supply side), whereas a Stimulus package is more Demand sided. Governments pumping $$ into Infrastructure and other projects would stimulate the Economy while maintaining a more "natural" Market by not tinkering with Success/Failure of Individual Corporations. Pour Cash out to the Masses(through Projects(Employment), not Cheques) and let them choose where to Spend the $$.
As mentioned before, I really think that Mailing Cheques out is not really all that helpful though. You must Do something. Employ People, Buy Supplies, Build something People can see tangibly. Increase Confidence and get People's focus off their Fear/Worry.
All that said, the Auto Industry Bailout might still be necessary. That Industry's situation has come to a head at the worst possible time when Bad News feeds on itself and creates more Bad News as a result. I think it's good though that the Government has been dragging it out with them. The situation is serious, but not near as serious as the Banking situation was and it is important not to get caught up in the moment and throw $$ all wiilly nilly. Unlike the Banks, the Auto Industry requires some Obligations for accepting Bailout $$.