do you mean $100k/year income or $100k assets or what?

100k saved somewhere is the baseline, I don't know enough about American prices to say about how much extra stuff should be worth. The most reasonable addition I can come with is no debt, or payments.

On a side note, I never really understood the whole "$x a year" thing. There are so many expenses during the year itself that what you made the whole year is pretty much irrelevant.