My goal for my 401k is to have $100k by 28, $500k by 38, $1M by 43, $3M by 54, and $5M by 59. I also have a modest pension that, if I continued to work at the same company for my whole career, would be worth about $42k/year at age 60.
That will allow me to live more than comfortably, any more than that and I probably wouldn't even be able spend it all. With 401k withdrawals, my pension, and social security, that comes to something like $275k/year, which is about $115k/year in today's dollars.
Beyond that I'd rather just save and invest in personal accounts so that I can enjoy my money before I'm all wrinkly.