Your employer probably limits the investment choices you can make in its 401(k) program. But individual retirement accounts (IRAs) allow you to invest in nearly anything you desire. Over the long run, investing in stocks is the best way to grow your retirement savings. But what stocks should you buy for your IRA?

Some investors prefer growth stocks. Others seek income-generating stocks. Value investors like bargain stocks. My view is to mix in all of them in your IRA. I think three top stocks in each of these categories -- NVIDIA (NASDAQ:NVDA), Iron Mountain (NYSE:IRM), and Celgene (NASDAQ:CELG) -- stand out as great stocks for your IRA. 

Golden egg with IRA written on it on top of $1 bills

Image source: Getty Images.

1. NVIDIA: A monster growth play

NVIDIA's share price has skyrocketed more than 1,000% in just the last three years. The graphics-chip maker's sizzling earnings growth might cool down somewhat, but Wall Street analysts still think that NVIDIA will generate average annual earnings growth of more than 23% over the next five years.

Three fast-growing markets should enable the good times to keep rolling for NVIDIA. One is the company's core gaming market. Digi-Capital projects that the game industry market size will top $230 billion by 2022, with hardware for PC gaming a big driver of growth. NVIDIA's graphics processing units (GPUs) are the leading chips for the gaming industry.

Another growth engine for NVIDIA is in data centers that harness the power of artificial intelligence (AI). More than 1,200 customers use NVIDIA's AI platforms, including several of the leading technology companies that are pioneers in applying AI. NVIDIA thinks that the addressable market for AI data centers should be $50 billion by 2023.

Self-driving car technology is a specialized application of AI that NVIDIA expects to fuel growth for years to come. The company has adjusted its self-driving car technology strategy to focus on providing end-to-end integrated hardware and software. NVIDIA's self-driving car platform has been selected by Uber and several major carmakers. Investment firm Goldman Sachs thinks that this market will increase eightfold by the end of the next decade.

2. Iron Mountain: Strong and steady income

My income pick for IRAs -- Iron Mountain -- is a dividend investor's dream. The company's dividend currently yields 6.54%. Iron Mountain has increased its dividend by 24% over the last three years and expects to continue growing the dividend by at least 4% annually in the future. 

Yield is just one part of the equation for an income-generating stock, though. You want to be able to rely on the dividends to keep flowing. It's also helpful if the stock has reasonable growth prospects. Iron Mountain scores on both counts.

The company ranks as the world's top provider of records and data storage, with 225,000 customers in 53 countries. Iron Mountain receives a steady revenue stream from these customers paying for it to store their records and data. Customers tend to stay with Iron Mountain because of the hassle of moving to another vendor and the company's solid track record. 

While Iron Mountain isn't likely to be the growth star that NVIDIA is, the company does have several paths to generate pretty good growth. Customers continue to produce more data and records that need to be stored. Iron Mountain also should grow in emerging markets and from its expansion into new areas, especially data center operations.

3. Celgene: One of the biggest healthcare bargains around

Everybody likes a bargain. I think that one of the best bargain stocks to buy for your IRA is Celgene. The big biotech trades at less than nine times expected earnings, a discount of more than 40% to the average forward earnings multiple of the S&P 500 healthcare sector stocks.

It's always smart to ask why a bargain stock comes with such a low valuation, though. In Celgene's case, the issue is that some investors are concerned that the company won't be able to generate enough growth to offset a future decline in sales for its top-selling drug, Revlimid. Currently, Revlimid accounts for 64% of Celgene's total revenue.

My view is that Celgene is less risky and more attractive than the market is letting on. First of all, Revlimid isn't likely to see generic competition until 2022 -- and then only in limited volumes. Celgene struck a deal with Natco Pharma to allow an authorized generic version of Revlimid to be marketed in the U.S. at limited volumes starting in March 2022. While other potential rivals are challenging Revlimid's patents, I fully expect the company will eventually come to similar terms with them. 

In the meantime, Celgene has two other fast-growing products in its lineup: immunology drug Otezla and multiple myeloma drug Pomalyst. The biotech also claims the No. 3 pipeline in the industry, with several candidates with blockbuster sales potential on the way. 

No stock is perfect

This is your retirement savings we're talking about, so you do need to know about the risks of each of these stocks. No stock is perfect. NVIDIA, Iron Mountain, and Celgene are no exceptions.

There's a chance that other companies could develop chips that prove to be better than NVIDIA's. Iron Mountain could flop in its efforts to expand into new markets. If that happens, paying down the debt the company took on to finance those expansions could be challenging. Celgene faces risks of pipeline setbacks and the possibility of losing its litigation battles over Revlimid's patents.

I'm not overly concerned about these risks. In fact, I personally own two of these three stocks (Celgene and NVIDIA) in my own IRA. I think all three are great picks for any investor's retirement account. Because of the risks associated with buying a small number of stocks, though, be sure to invest in several other solid stocks, too.