Source: Flickr user Ervins Strauhmanis.

The main reason people invest is to achieve financial security, and while getting "rich" can be a moving target that depends on each individual's definition of the word, investors aren't likely to turn down wealth-boosting stocks. So we asked three of our top Motley Fool experts to tell us which companies they think could make them rich, and their answers cut across travel, dining, and finance.

Dan Caplinger
One stock I've followed for a long time is Chipotle Mexican Grill (NYSE:CMG), the fast-casual restaurant chain that has taken the industry by storm. Even as traditional fast-food outlets focused on efficiency and cost savings, Chipotle emerged with a fresh emphasis on high-quality food, and customers quickly flocked to the burrito maker in droves.

Chipotle's growth trajectory has been stunning, with net income more than doubling between 2011 and 2014 on revenue gains of more than 80%. Yet even as Chipotle has gotten bigger, its growth rates have only slowed down a bit. In its most recent quarter, Chipotle posted comparable-restaurant sales of 16.1%. Admittedly, Chipotle said it expects growth in comps to slow in 2015, but even so, expansion plans for between 190 and 205 new locations should keep the Mexican food chain climbing higher. Moreover, the company has shown a remarkable ability to keep its loyal customers even in the face of price increases, even as competitors have to deal with food inflation and the uncertainty of whether customers will flee if menu prices rise. With the eatery having proven overly pessimistic in its guidance in the past, Chipotle has a lot of potential to keep growing into an international powerhouse in the years ahead.

Selena Maranjian
Among the stocks in my portfolio that I hope will make me rich is Priceline Group (NASDAQ:BKNG), the online travel-booking giant. It's been a great performer for a long time already, averaging about 48% annual stock-price growth over the past decade -- though it's down some 13% over the past year, presenting an appealing buying opportunity. Its recent forward-looking P/E ratio is 15, which is about half of its five-year average P/E.

The company is firing on all cylinders, with gross margins rising over the past decade to nearly 89% and net margins rising to 29%. It's generating about $2.6 billion in free cash flow annually, and its revenue has averaged an annual growth rate of 29% over the past five years, with earnings-per-share growth averaging 55%.

Priceline is well diversified: The lion's share of its revenue is generated outside U.S. borders, and its international bookings recently grew by more than 30% year over year. It's also diversified across flights, hotels, car rentals, vacation packages, and even restaurant reservations. It's been making some promising purchases over the years, too, such as and -- and OpenTable last year.

So why is the stock down lately? Well, some are worried about weakness in Europe and China and currency translation issues owing to the strong dollar. However, those are not lasting problems. Some also don't like the company's increased marketing expenses, which can shrink profit margins. But that doesn't worry me much, as Priceline's margins are huge to begin with, and marketing money well spent can be cost-effective, building the business.

Priceline reports fourth-quarter results on Feb. 19. In its last quarter, revenue surged 25%, beating analyst expectations, while net income jumped 38%. I'm happily hanging on to these shares.

Jordan Wathen
I think there may be no better long-term investment than Visa (NYSE:V). The company's business model is incredibly attractive: It works as a "toll booth," collecting a fee on debit and credit card purchases on its network. Over time, fewer and fewer payments are being made in cash, giving the company a natural tailwind for growth without any new capital investment. Growth is as easy as watching shoppers slowly shift from cash to credit and debit.

There are risks, of course. Regulators have cracked down on what they saw as excessive debit card fees, and credit card fees could be subject to future regulation. And other payment platforms like Internet stalwart PayPal and up-and-coming Apple Pay are worthy competitors.

However, the global-payments business is a very big pie, and if Visa can merely keep its share, it can produce excellent long-term returns for shareholders. And it has levers it can pull to remain competitive. Its operating margins, projected above 60% for 2015, give it room to compete on price. Likewise, its capital-light business model allows it to give virtually all of its cash flow back to shareholders in repurchases and dividends, bolstering its share price potential. If it can avoid the regulators and hold its competitive ground, long-term investors will be rewarded handsomely.