A number of top investment strategists offered their opinions about the market and the economy at the recent Morningstar Investor Conference in Chicago, including value fund star (and Benjamin Graham disciple) Mario Gabelli.

Gabelli, whose ABC fund posted its first negative returns in 14 years last year — when it dropped just 2% — sees opportunities in the market for long-term investors. “Basically we are very simple: What will the stock market do over the next ten years?” he told MarketWatch.com. His firm thinks gross world profit will grow at about 3% going forward, with inflation of 3%. Margins will be “a little challenged” and taxes will rise, but profits will still grow at about 5% or 6%. “Valuations are reasonable today on normalized earnings, so the markets are going to grow 7-8% total return to an investor today,” he says.

Gabelli said his firm does intense research into small- and mid-sized companies, and sees a round of consolidation and takeovers that will add 3 to 5 basis points to those returns. He said stocks still have a wall of worry to climb, as they always do, with issues like fuel prices, North Korea, and Iran having the potential to derail the market. But he thinks that the global efforts to address the financial crisis will eventually work, and he sees companies worth investing in.

Gabelli was far from the only one to weigh in on the markets at the conference. SmartMoney offers a good, concise summary of what some other top investors had to say. As you’ll see, some shared Gabelli’s opportunistic view. Jeremy Grantham says he sees good values in emerging markets, for example, while Ron Muhlenkamp likes a number of bargain blue chip “Cadillacs”. Others had a gloomier view. PIMCO bond guru Bill Gross said he foresees a new world where “investors won’t be the winner”, for instance, while FPA’s Bob Rodriguez said the U.S. could even see its credit rating slip in coming years.