Investors have officially shut the door on the 2015 trading year — albeit with some pretty lackluster returns for the major averages. Although the Nasdaq finished up nearly 6 percent, the Dow Jones Industrial Average and finished the year close to where they started.

That said, those looking into the distance and focusing on long term investments may not be too concerned about this year's relatively flat performance —especially millennials who may be set to jump into the market in the new year.

According to a recent Bank of America study, 82 percent of millennials say they will invest more in 2016. So where should they be looking to invest for the long run?

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Francine Lai, a financial advisor at Gerber Kawasaki, said if investors are looking at stocks for the next 50 years, they should be focused on what she calls the "blue chips of the future." She thinks Facebook and Netflix are great fits for young, less risk-averse clients.

"These are exciting companies. Millennials like to buy companies that they know, companies that they are familiar with. Facebook is exciting, growing and a blue chip of the future," she said on CNBC's "Closing Bell" recently. "I don't think they are going anywhere. If anything they are gaining traction."

Yet given rapid shifts in technology and social media, Steve Dudash, president of IHT Wealth Management, doesn't agree that a company like Facebook will be around in the coming decades.

"I want boring companies," he said. "If we are trying to talk about something for the next couple decades, I can't look you in the eye and tell you Facebook is going to be here in 20 years."

Despite the recent collapse in oil prices, Dudash believes British oil major BP is a stable investment for the next half century.

"Basically we are looking at what sectors are going to be around for a long time," he said. Even as a flood of oil has driven down global crude prices and heaped pressure on oil producing companies, Dudash thinks the smart money is still on big oil names like BP, which fell by nearly 14 percent in 2015.

"I know oil is the big talk and it's not doing very well but it's not going away, oil is still king of the castle in the energy sector right now," the analyst told CNBC. "BP — you can get into it with a very nice dividend and low valuation. You can put it in your portfolio, leave it there for decades and know it's going to be strong."

Although he doesn't like Facebook, he still does see some opportunity in the tech space for those with a long term investment horizon. His tech pick is Alphabet, formerly known as Google.

"Alphabet isn't just the largest most relevant search engine but they are growing outside of that world," he said. "They have even gone as far as changing their very well-known corporate name to reinforce that they are expanding outside of that world."