A ton (perhaps most) failed businesses fail because they're undercapitalized. Even if your costs are low you can only go so long without eating, and if you're worrying about how your life savings is going to run out in 4 months I guarantee that you won't be as effective at building your business.
Your chances of bootstrapping a successful business are much much higher when you have money.
The best thing you can do is not start up a different kind of company (bootstrap vs. VC) but build up your bank account. In this market there are a lot of opportunities to earn good money, particularly if you're a developer. Save, save, save and in a few years, you should have enough to start a business from a credible, realistic cash position.
Amen. Although, my approach is to be working full-time making a good salary, but spend my nights/weekends working on my business and investing my savings into it. I'm not going to do it full-time until I start making good $ with it.