If you are retiring from a job where you have a good amount in a 401k or 403b with that company, it ends up being better. The rule of 55 plays in where you can take that money out as long as you worked at the job a day after turning 55 and that withdrawl doesn't require paying the 10% tax penalty.

Most people put their money in the 401k and don't have the other investments to cover the gap between when you retire and when you can touch your 401k without penalty. Even if you're just putting $200 a month into an investment fund outside of your 401k, that money can help you considerably to help fill the gap.

You mentioned net worth, which would include your house, but I wouldn't include that in the discussions unless your planing on downsizing. Also, if you're close to retiring, you may want to consider updating your house while you're still working. Most houses (including the one I just purchased) are dated 20+ years when people want to downsize and that could considerably hurt your sales price or how quickly it sells.

You are right about health care and the market place for non-employee policies is downright criminal. The Affordable Healthcare Act was an overall good think in many ways, but at a huge price for 97% of the population. People saying insurance costs wouldn't go up and coverage wouldn't change were nuts.

In the end, the answer is somewhere between $2 million and $3 million if you are over 40. If you're under 35, it's probably above $3 million. Younger folks need to max out their 401k as quickly as possible and especially max out any company match they may have available.