If we recall the terror attacks in mumbai by pakistanis and also the al shabaab activity in our region,I think war with Iran will bring out all these terror groups in droves across the region from India to East Africa - anywhere with western interests or western sympathisers.
At 9/11 it was really just the US - after that we have seen the net getting cast wider to include pro-US countries - remember Bali? Remember the Cricket team attack? If Israel dares attack (or is encouraged by the US) to attack Iran,that will be the last straw...we were hit in 1998 for simply hosting an embassy (likewise Tanzania)....how much better off are we now,especially having let our own be profiled and shipped off to Guantanamo bay?
Israel already has the Palestinian militias chipping at its sides,a dozing Egypt that can awaken,Libya,Sudan that has been criminalised,etc the US is already OVERCOMMITED in Afghanistan (where that war is already turning into another Vietnam) and also in Iraq (where everyone is literally having a blast). Trouble is brewing in South America (Honduras,Venezuela - even Brazil is stepping into the foray to help Honduras).
China is HUGE and while it may not take any sides,it may choose to be neutral if only to benefit from the spoils of such a war. Russia still remains a wild card despite efforts by the US to 'reset' relations with it - they remain an unknown quantity. Oil will go up,cost of business too (costly products),cost of living (less buying power,less earnings)
The problem with equality is that we desire that it be with those that have more than us rather that those that have less