Let's evaluate the base assertion: "we should accept intelligent design because all cultures had a belief that creation was the result of some intelligent being".

First, a couple of the more entertaining Egyptian theories:

My personal favorite because it so precisely frames the meaning of the word "intelligent" is Atum, "who made everything (even himself) of his own sperm through masturbating". Yep, that's intelligent!

The other very illustrative one, also Egyption, was Khunum, who made the world from mud taken from the Nile (so the Earth already existed when this really smart guy grabbed some mud and made the world). Just how intelligent was this Khunum thing?
http://www.nemo.nu/ibisportal/0egyptintro/1egypt/

The Greeks were a bit too creative for me to find their intelligence and too complex for me to summarize here so read for yourself and let's see who can spot the intelligence in this design. Was it the brilliant act by which "the unknowable place where Death dwells" slept with "Night" who produced Doom, Fate, Death, Sleep, Dreams, and the god of anger (Nemesis)? How intelligent was that?

Or was it when Gaea (the Earth) and Cronus (not the timekeeping system) ambushed Uranus and castrated him, throwing the offal into the sea? A move clearly calculated to make Uranus a better father? I mean, how much more intelligent can one be than to want Uranus as a father?
http://www.greekmythology.com/Myths/The_Myths/The_Creation/the_creation.html

Romans? Well, under they're theory, it was all here alreay; they're god just gave it some order, rolling "stuff" into a ball to make earth (what 2 year-old doesn't know how to make mud pies?) Not particularly intelligent, but a darn good mechanic. Also organized all the other "stuff" to bring about harmony. A kind of community organizer. So the Roman god was simply the precursor to Barack Obama!
http://www.ehow.com/info_8243452_creation-myths-ancient-romans.html

Buddha just didn't want to think about it; wasn't a topic of enough importance to be considered (so, amazing as this intelligence must have been, it wasn't intelligent enough to learn from it).

http://www.sciforums.com/showthread.php?96097-How-does-buddhism-explain-creation

And then, of coure, we have the Bible, which has 3 different versions in Genesis alone and apparently spawned 8 or 9 (depending on how you count) generations of people coming from the same womb (Eve's) or just spawning from all those hoary old men emulating Atum to begat this and that but seemed never to get around to begatting a second woman. Real intelligent to just keep on masturbating instead of making at least one more woman to help out around the boudoir!

"The white men were as thick and numerous and aimless as grasshoppers, moving always in a hurry but never seeming to get to whatever place it was they were going to." Dee Brown