I graduated in Summer 2009, and I immediately wanted to do my own startup. I'd recently built my own new website, which was pretty much all my social networks on a single page. A friend asked me when he could have his, and after that I knew I was onto something. It turned into OnePage (http://myonepage.com) and it is doing well, with thousands of users. The problem? revenue was an afterthought, so to fund it I had to keep doing contract work. I tried doing it part time, and then I tried doing a wave of full-time and then a wave of full-time work on OnePage. We tried applying to incubators, too. After a year and a half, I still know there's huge potential in that space (just look at about.me), but I know I need to sort out my income so I can focus.
So, when the November Startup Sprint popped up, the timing couldn't have been better. I built my second startup called Buffer (http://bufferapp.com) with the sole purpose of getting to ramen profitability and using it to free my time. I built the app in about 7 weeks of evenings and launched with payment options from day 1. Fast forward one month until now, and I've had just over a hundred signups, 3 of which are paying. I have a long way to go, but I think this is the method more people should take.
Some people want the lifestyle business so they can spend less time working and enjoy life more, others want their finances "sorted" so they can hit for the home run. Either way, I think lifestyle business first is almost always a good idea.