I would love to know where that came from...

Basically, I think the general public is really mistaken about how much a war or conflict helps the defense industry.

Hmm. Estimated cost of war $75B. GWB has asked for $2.5B of that to be humanitarian aid.

We're already paying the military personnel out the standing defence budget.

So where will that $72.5B go?

Yes, you have a valid point that most of the platforms are 'long lead time'. But I think you're missing the point - there's a limit to how many and what kind of field repairs can be made to vehicles before they get returned to the manufacturer for maintenance and an overhaul. There's also a limit on flight hours for aircraft. And we know that those aircraft are making a lot of sorties.
Manufacturers make a lot of money from maintenance contracts and spare parts. I daresay that Boeing are going to make some significant cash from that Apache raid yesterday. '3 dozen or so' Apaches, all returning with small arms or AAA damage (the one that didn't return will make Raytheon $1m or so too).

The fact is that military readiness and the ability to fight two wars simultaneously is, and has been for at least a decade, a kingpin of US Defence Policy.
If the Pentagon *doesn't* spend most of that $72.5B at the arms bazaar, I think that the US taxpayers will want to know;

a) How the military can complain about being underfunded when it obviously has enough stocks and supplies to fight 2 expensive wars simultaneously without affecting future military readiness.
b) Why the President increased Defence spending by $48B this year. To put that in perspective, Russia is the World's number 2 military spender, and they only spent $65B *total* last year. http://www.cdi.org/budget/2004/world-military-spending.cfm
c) Where *did* they spend it???