You guys are forgetting one very important factor!.
Iraq is an arab nation. Iran is Persian. Believe me its a BIG factor.
Wars results depends on people's characters at the end.
No matter how superior weapons the others side have.
History proved that countless times.
I will not go on and say that iran can defeat USA or something.
I am just saying that the war with Iran will not be same as war with Iraq.
At Iraq the army of them almost totally "vanished" at the moment USA tanks started to roll. They even burried their migs and sukhois to the sand.
Like i said. The war with Iran would be nothing like the war with Iraq.
My 2 cents..