I moved here one year ago from Italy. Got an apartment from my first company for 2 months, then rented a shared apartment with other two people.
After a few months I got a mortgage with no money down and moved in my own house not far away from the center, and the government reimburses me part of that every month.
If we speak about renting prices, I can agree they are high, but from what I heard they are still less expensive than in the valley. Places to rent also go really quickly, but impossible is another thing.
I have a ground level apartment with a courtyard on the canal at Groenburgwal, which is in my opinion the nicest neighborhood in Amsterdam, right smack in the middle of everything, but quiet, and beautiful.
Furnished, all inclusive: €1300/mo.
I lived in San Francisco. An apartment this nice in a neighborhood this nice was well out of my price range, and I made six figures at Apple.
People keep bashing US's immigration system, but the only country I know that it's easier on immigration for skilled workers is Canada. If you have the requirements then you can move without a company sponsorship, and then look for a job.
As far as immigration is concerned, one can fall under the category "kennis-migranten" (loosely translated as knowledge-workers) pretty easily, as long as the company sponsoring you is willing to pay the money, around 50K (Pay is not like the Valley, but I'm guessing this is doable).
There is the possibility of starting a company as an American citizen due to a WW2-era Dutch-American Friendship treaty (see http://www.expatlaw.nl/dutch_american_friendship_treaty.htm)
As far as startups I know of in Amsterdam, there is Fashiolista, and Sofa used to be there...