I think a good way to approach this is not the cost in human lives, but in monetary cost. $200B/300M Americans is $666.00 per person, $2,664 for a family of 4. Has it been worth it?
The annual cost is say $400/year... are YOU willing to pay another $400 in 2005 to support the Iraq War?
For the vast majority of Americans, $400 is not an amount to be casually discarded. $400 could buy:
groceries for 2 months
A year of cable
A completely new wardrobe
A major repair for a car
Lessons for a child
I welcome any additional analogies and am eager to hear where my figures might be wrong.