As an adult, I've personally lived in Boston, Seattle, San Francisco, New York City (where I now reside), Los Angeles, and Boulder, Co. If I had to chose one, I'd chose Boulder. Why?

- Great tech scene.

- Great VCs (Brad, Ryan, and the rest of the Foundry Group are a great bunch of guys).

- Great weather (unbelievable amounts of sun every year).

- Amazing hiking just 10 minutes outside the city. Go a little farther out (30-45 minutes) and you can follow some trails that will take your breath away (figuratively and literally :-).

- Great skiing close by if that's your thing.

- Great food -- not a ton of choices, but some good choices.

- Very quick and easy access to a major airport with cheap daily parking (about 45 minute drive and if you take the tollway, you'll never -- and I mean never -- have any issues with traffic).

- Easy access to both the east and west coast.

The downside is that Boulder is a bit homogenous. There isn't a lot of racial/ethnic diversity in my humble opinion.