Ok a more serious answer...
Say we do topple saddam..
How long will we have to stay there?
I would think that would largely depend on how much faith the country has in whatever leader we put in place and if we can keep the poor guy ALIVE without being assassinated. (wouldn't want to be him!)
We'll probably put in a pawn so he can get shot, make everybody happy and then put in a real leader.
Do we do the whole give them a constitution thing as well?
It WILL take time and $$$$ for all of this to work out. I don't know where Mr. Bush is going to squeeze it out of. HEY I know a great place! Education! Social Security!

Ok say one year, we pull out we're happy with the country...
How long then, does it take them to backstab us and turn against us again?

Considering the amount of rage in that entire area against americans could they really have a country there that likes us?
I'm guessing not.
If we weren't totally supporting Israel they'd be in line with the rest of them to terrorize us