Marc Andreesen, the developer behind the original Netscape browser, and now Silicon Valley pundit, wrote a blog post that contains the essence of success in building a company:  Build something worthy!

His overall post is about the effect of the proposed Microsoft acquisition of Yahoo on Silicon Valley's startup "machine".  He believes, as do I, that it will have little effect since (a) the big guys aren't acquiring many startups these days and more importantly, (b) don't build a company to "sell it" build a company tha makes something people want to buy!