In Boulder itself houses are far from affordable (but also still far below Bay-area prices) due to growth restriction, but since Boulder is very small in terms of land area the surrounding towns are an easy commute compared to anywhere in the Bay area. And while the locals like to complain about getting scammed out of commuter rail, the existing bus mass transit to and from Denver and the suburbs along Highway 36 is really pretty decent (albeit expensive unless your company or company's tax district subsidizes the pass).
Come to Boulder. While rents in the Denver area have been climbing recently, they still fall short of the craziness of SF/NY (some facts, here: http://www.denverpost.com/business/ci_28740315/denver-area-a... "median price for a two bedroom is $1550") . And we have 4 real seasons and skiing, unlike LA.
If you want startups, Boulder or downtown Denver are pretty good, or if you want more established tech companies, Interlocken or the Tech center are where it's at.