How should I invest $125,000 to make the most (money) profit?

I would like to invest a minimum of 2 yrs. up to a maximum of 6 yrs.

Your question is hard to answer because it does not say how much risk you are willing to take. You could buy $125K of a single company's stock. It may double in two years or become worthless. If you spread the funds out over 10 stocks, then the probability of loosing it all is less. Investing in land or properties has usually been safe as long as you are familiar with the market. I friend of my invested in realistate in Florida 2 years ago and now the property has dropped in value. He bought at the top of the market with all the hype.
You can place all of it into a savings CD and get 6%/year. Assuming that inflation is 6%, then in 2 years it will be worth the same amount. You have risked nothing, lost nothing but gained nothing.
I am investing in the stock market using technical analysis to determine when to buy and sell. I am making about 30%/year. It takes a daily commitment to make buy-hold-sell decision. I am only doing this because all my other finiancial needs have been met and I am investing with money I can afford to loose.

buy property in a growing community

Buy land!!

For a more steady profit and almost no risk, you can put it into a CD.

You should get a few books on the stock market. Do some paper trading. Meaning, practice with artificial money. If you search "stock market game" you'll find a lot of ones offered online. Try that for a good few months. Read some books. Toni Turner rights some great books. Take a look on Amazon. WIthin a few month of practicing you can start trading some big board stocks and make good money doing it if you've trained yourself well. If you have any other questions, let me know. I'd be more then happy to help you.

Hire a Portfolio Manager with over a decade of experience in the Stock Markets like myself.

well normally I would tell people to buy property......but if you live in the US there is a housing slump right now.

There are many options, you could either buy oil or gold. Even invests in hedge funds. But for minimum risks involved, I suggest you change your USD into GBP (Pounds Sterling), open a British Pounds account with your bank (HSBC would do this easily) and put all your Pounds Sterling into that account. wait a couple of years and close that account to retain your money back in USD. GBP is very bullish and I am very confident will stay bullish agaisnt the sloppy USD in the next couple of years.

How much risk are you willing to take?

Two years is too short to invest in stock market, so you need to put it in a ladder of CDs.

If you have six years, and you want to be a bit more aggressive, invest it in these Exchange Traded Funds (ETF)
1. SPY -- S&P 500 ETF
2. MDY -- Midcap 400 ETF
3. IWM -- Small Cap 600 ETF
4. EFA -- Int'l Developed Markets such as Europe, Australia, Japan.
5. EEM -- Int'l emerging markets such as Korea, Taiwan, China, Mexico, Brazil, India, Russia

If you want to speculate even more, in addition to putting 60% of your money in the ETFs before, you can invest in individual stocks:
6. AMX (America Movil)
7. GME (Gamestop)
8. NTRI (NutriSystem)
9.GOOG (Google)
10. AAPL (Apple)
11. HANS (Hansen Natural)
12. NVT (Navteq)
13. BA (Boeing)
14. SZE (Suez)
15. GILD (Gilead)
16. GS (Goldman Sachs)
17. LUK (Leucadia)
18. SNDA (Shanda Interactive)
19. COP (Conoco Philips)
20. BTU (peabody Energy)
21. ESV (Ensco)
22. PEJ (Leisure and Entertainment ETF)
23. TDG (Transdigm Group)
24. FWLT (Foster Wheeler)
25. FCX (Freeport McMoran)
26. HXM (Homex)
27. WBD (Wimm Bill Dann)

This is more aggressive, of course.

If you want a bit more caution for 6 years,
invest in:
1. SPY
2. MDY
3. IWM
4. EFA
5. EEM
6. 50% of portfolio in bond mutual funds.

So 50% equities, 50% bonds.

Your choice where you want to be in the risk-reward spectrum.

aid4families.com pays 120%APY. Your deposit is guaranteed and I know several people who swear by this program.

Check it out for yourself

You can go with Prosper (p2p) lending and get your money on a loan (up to 29%) for three years. Sign up through the Heroes Group and get $25 added to your account.

EDIT: first, if you have any cc debt, pay that down. That's an immediate 18%+ return on your money.

Take some classes. 888options.com has a list of upcoming FREE seminars. I've been trading some options recently with some success. Also, a newsletter or two probably wouldn't hurt.
DON'T rush and get in before you're ready and lose more than you're willing to. Use trailing stops. 2-5 years should really not be in the market, thats more of a disposable income time frame, CDs and the like. But with the yield on some MM accounts so close to CDs, the ability to have instant access to your funds in the MM is worth the .3% lower yield in my opinion.