Probably, but it's hard to say without reference to a specific believable alternative reality. The only thing I can think of that I'd have traded it for is an opportunity to make serious money (as in, being worth north of 10mm right now in 2012) at critical go/no-go moments. I had three such moments, in 1997, 1999 and 2000. No exceptional opportunities presented themselves at those times, and I had no bright ideas of my own to create such opportunities.

Money is the biggest thing you give up if you get on the PhD track. Your twenties are your prime big-money decade. PhDs put you on a track for being far poorer than your average peers by age 30. By then, they've been at least putting money in 401(k)s for 8 years. You exit the PhD basically penniless.

It's a financial handicap you may never overcome. Money increases in importance as you get older and opportunities to make lots of it get to be fewer and far between.

Overall though, no regrets. I can safely say, upon candid reflection, I've never had what it takes to make big money in the three regular ways: Wall Street, do-or-die entrepreneurship, or extreme careerism. The irregular ways are age-agnostic, so I still have a shot at those. So my real opportunity cost was missing out on the average Joe Schmoe of doing your twenties, and being a few 100ks behind in the Net Worth game as a result. Was the PhD worth a few million in the Net-Worth-at-65 stakes. Dunno. We'll see.

Whatever you decide, try to decide based on the assumption that money will be far more important to you in the future than it is today.