Check out my apps at: http://www.squarepoet.com/
My best performing app is Tiny Piano, which recently reached 2 million downloads: http://itunes.apple.com/app/id477014214 I also recently updated my Japanese learning game: http://itunes.apple.com/app/id492005575
My company became profitable starting this June. Tiny Piano has made enough revenue over the past several months to pay all my bills, though revenue is dropping fast. :-) That's how the App Store works... you get an early bump and then your downloads begin to trail off.
I left my full-time job 2 yrs ago, and so I spend most of my waking hours hacking on apps.
I'm a pretty competitive person, so wanting to "win" or wanting to "not fail" keeps me motivated enough. I have a few concrete goals that keep me focused. 1) Get 10M+ downloads so I can say on my resume that I made a "hit" app. 2) Buy a house in the Bay Area. :-)