"followed by Cambridge/Boston" -- really? When I lived there, it was very very hard to find technical people that were not "corporate drones". I new maybe of only one or two startup (I am not sure they ended up anywhere). Most other companies are "enterprise oriented", such as VM-ware types.

I remember attending few session at an incubator close to MIT campus. The speeches were given for people that had build products like "scanners" for airports, and government etc.. not software oriented One thing I remember, this guy from HBS, with a very smug attitude ( maybe b/c he got into haavad he thought he was better than everybody). Not a hacker friendly atmosphere at all. Most people there were the "business" types, that had "ideas" and buzzwords, but very low on concrete implementation and treated technical skills just as a commodity that could bought off in India.

Boston is not "eccentric" and "whacky" enough to support an environment with lots of startups with crazy and novel ideas.
Here is few facts:

You don't see naked people in the streets on Boston's fairs. It is mostly family/9-5-er or young students, which tells you about the general population of the place. If you are in your mid 20s, and out of school, it is not a good place to be.

You can't buy alcohol on Sundays You can't have wine/beer in a coffee place (Puritanism at max)

Most coffee/food places around Harvard sq. and Davis sq (the artsy part) closed by MIDNIGHT!!! WTF? Most good programmers I know are most efficient at midnight, and having things/places to get "fuel", (coffee and food) and some re-energizing is very important.

For many reasons, I think NYC would be a better place for a startup, if it wasn't so damn expensive, which kills ideas that have no business model right away. But as a place is very vibrant, lots of stuff to do, good looking women, and lots of money around, which are motivators for people to try harder and make it happen.

The only thing that the Boston/Cambridge are has is it's student population. -- which not surprisingly moves out somewhere else after school, and that it is a very walk-able city. You can walk to places, take the T (subway), which is very cool.

Personally, I like SF a lot, but I would never live in the South Bay. All those seas of parking lots and the "drive everywhere" culture is very depressing and soul drenching. Efficient for big corporations like HP and Yahoo, but I can't see it being good for a small start up.
My preference for startups: SF beats them all. NYC second (if it wasn't so damn expensive), but it has bonus point for being so close to the old media advertising, then Cambridge/Boston (for having so many college kids around).

I think, Eastern Europe is going to become more prominent in the IT world. You have lots of smart and well educated people at sciences, still cheap, and with a good sense of entrepreneurship (unlike India or China, which see life more as a career, eastern europeans are new to capitalism, and view this time as a great opportunity). It will take a decade or so, but you will see more things coming out from places like Hungary, Croatia, Romania etc. I doubt it will ever be a single large European "hub".

Edited for spelling, and adding some content.