[yourabi]

Live cheaply while you can (SV is not cheap)

When you are ready to start hiring and getting outside investment move here.

There are also other more local startup hubs, don't forget that last.fm was founded and still is in london. If your idea has wings I don't think a US company would care where the offices are.

[scylla]

While expensive by American standards, SV is still cheaper than Amsterdam. Of course, if you're still iving with parents or have a house purchased decades ago, then things are very different.