I think at one point SV had 10x more capital than NYC. The difference is slowly decreasing.

(I moved from NYC to SF to start a company.)

Another big reason I see that NYC will catch up is that you just dont need that much to start a company. And also VCs are beginning to have offices in both areas.

The only real difference is the ease with which you can meet someone really important in SV. You can get an introduction to PG through one of his startups within the week if you can show you have some traction and get the respect of some founder he has backed.

And all said and done, startups are realizing that investors dont matter - creating a product that people want to use is the bottom line. If the costs are low and you can afford it, you might as well forget about having to deal with VCs and investors except for advice.