Pay down my current mortgages/pay off personal residence and buy more "buy & hold" properties to rent out. And go on a 2 week vacation to Portofino, Italy or Kyoto, Japan.

Buy myself a few multi family properties and expand into some new areas of business I have been wanting to get into. Maybe even get back into options trading myself, I did good with that in the past but am just working on building my brand right now.

Good question!  I think I'd invest in a good financial advisor!  Surely can do better than <1%.

Tax free?  Since we are already fully invested, I would have some fun with it.  By fun I mean buy some properties at Trustee Sale on Court House steps, and flip them.

I have my eye on a few good investments.

I would probably take 1/2 of it to pay down some remaining debt I have from loans on my biz (so I wouldn't have to worry abt those) and invest majority of this half in my business/new business.  Given my age, smarts and income potential, investing that in my biz would be one of the smart things I could do...so that I'm earning more money on yearly basis to invest more as I'm going along (for next 20 yrs or so).

I would invest the other 1/2.  I already have some money in 401K's and retirement funds.  But, with the $500,000, I would (for now), 80% to index funds prob S&P 500., $20,000 for myself, and remainder in bonds or something similar.

I would add it to my professionally managed retirement accounts. 

Put it in an investment for retirement.

R-E-T-I-R-E!

I have plenty of investments waiting for every available dime, and I do keep my money busy.

The answer is simple: Invest in Real Estate.

Do you have an spare million? I'm open always willing to accept $$$ donation:)

REAL ESTATE!!!  I'd buy and fix up a few more rental properties, maybe flip a couple.  Isn't anything out there like real estate for long term appreciation and cash flow.

I'd put in in a mutal fund. 

I would invest in real estate and put the rest into retirement funds.

Owning anything free and clear is the best return on investment

Put it in investments. Some RE some stocks, bonds, ect.

John - Well I don't think I would pay off any debt, because I actually don't have much to begin with. I would much rather invest that money into real estate. Perhaps some fixing and flipping, maybe another rental property or two, and perhaps investing in some sort of business that I could own.

I would much rather try and make tens or hundreds of thousands of dollars each year out of that million, than to pay off some debt where I am maybe paying a couple thousand dollars in interest each year.

Of course I wouldn't spend it all, perhaps save 25% just in case.

Pay off all debts, buy a couple investment properties, take a nice vacation, and throw the rest of it back into my business.  I'd probably give $100K to my financial advisor and trust him to do his thing.

If it was my only savings, I'd probably get a good life annuity with a guaranteed return and payout.

I'd probably invest some of it in the stock market.

Definitely invest in real estate and put some of that money in my other businesses. 

Buy a modest home, travel more to see my East Coast family, give a good chunk to charity, and invest in retirement and interest-building savings. I would definitely take a little trip around the world, since I've only been around (not out to Hawaii or Alaska yet) America and two cities in Canada, so far.

Good question. This modest 1300 sf SFH is one of the most affordable homes in SF South Bay  CALIF MODEST HOME. It would sell around $0.65M-not the best neighborhood.  No serious crimes. Go a few miles west to job center.  It will dble that value. Same home for $650K or so you get $2500. Go further west you can get a small loan and rent it for $3500/mo?  You can do the math.. Expect 12-15% appreciation for the next 2-3 yrs.... No recession in the horizon....

I must first consider the source of this million dollars.

If I did not earn this money, I must understand it is not mine.

If that million is a result of my effort, will would continue the same efforts that earned it, but on a larger scale. Healthcare, healthcare middleware, defense, government middleware, food supply (ie:Monsanto) are no-brainer investments.

If I did not earn the money, I would invest it in people.