I have the same reasoning as you. The number will be whatever amount that generates the income to support your desired lifestyle. This could be in investments or low involvement business income. Thus the number for me is 2.5 million based off of 4% dividend for a 100k income (about single engineer middle class Bay Area only because dividends are taxed lower). Or a number of side businesses that add up to that income.
I love the idea of "a number of side businesses that add up to that income". Small, simple businesses that generate enough to make the ideal lifestyle possible. That's a strong goal. It's especially good considering your dividend-based alternative. I'm sure you've noticed that dividend stocks are getting hammered right now. :)
Yeah, both fortunately and unfortunately I expect myself to be able to sooner build small business income to 100k than amass 2.5 million. Not that either is easy of course. Or even a reasonable expectation.
I wouldn't worry about stock price as you hopefully never have to sell a good income payer. But if you are buying, at some point a good dividend payer will fall until it's cheap enough for a good return, ie wait for the next crash. I think the dividend stocks are being sold off now because of uncertainty over tax rules in 2013 for dividends, and also since money has been chasing yield and made those stocks overbought.