Steady income quarter after quarter can add up to big bucks over the long run. That's why dividend stocks make up an important component of many investors' portfolios. But which dividend stocks are good candidates? To answer this question, we asked a couple of our contributors to pick two great dividend stocks you can buy right now. Here are their thoughts.

Matthew Frankel: Some of the best dividend stocks you can buy now are REITs that specialize in commercial properties like National Retail Properties (NYSE:NNN).

Commercial real estate has several advantages over, say, residential properties. For starters, most tenants sign longer-term leases of 10 years or more (National Retail's average remaining lease term is more than 12 years); meaning that the turnover rate is much lower and rental income is steadier. And, tenants are on "triple-net" leases, which means tenants are responsible for property taxes, building insurance, and maintenance. Basically, all National Retail Properties has to do is collect the rent.

National Retail Properties currently pays a 4.4% annual dividend, and has raised the payout for 24 consecutive years. The company owns 1,927 properties in 47 states and has an outstanding 98.5% occupancy rate. This type of diversity means the company's success isn't tied to any one tenant or geographical area, and it also shows that the company's properties are desirable enough that it doesn't have a tough time filling them with retailers.

Not only do shareholders reap the benefits of rental income, but as the company's properties increase in value, so does the value of the shares. This is a great play on both the recovering U.S. real estate market as well as the trend toward higher rental prices.

Plus, commercial real estate works well in all markets, good and bad. Thanks to the long-term leases I mentioned earlier, automatic annual rent increases are already agreed upon. So, while an apartment complex might have to keep rent steady or even lower it during bad economic times, commercial properties don't really have the same problem.

The proof is in the performance. Over the past 20 years, National Retail Properties has averaged a total return of 13.4% per year, handily beating the S&P's 9.8%.

Over the long run, the favorable business model of owning a diverse basket of commercial properties can produce consistent, strong returns that will still let you sleep at night. 

Keith Speights: Matthew's right -- investors looking for solid dividend stocks should consider REITs specializing in commercial properties. One stock worth a serious look is Medical Properties Trust (NYSE:MPW).

As you might expect from its name, the company focuses on healthcare-related properties, especially general acute care and long-term acute care hospitals. Medical Properties Trust's current dividend yield of 6.2% rates among the best in the market.

One great thing about this REIT's properties is that there isn't a huge risk of near-term churn in tenants. At the end of 2013, over 85% of Medical Properties Trust's lease portfolio had leases expiring no sooner than 2020. Well over half of these leases extend beyond 2023.

Medical Properties Trust is still in growth mode. The company continues to build and acquire new properties in the U.S. and in Germany. Recent activity includes picking up 38 rehabilitation and two acute care hospitals in Germany, plus completing construction on eight emergency room facilities in the U.S. With aging populations in both countries that should increasingly need healthcare services, this growth strategy seems smart.

The company also makes money from financing real estate transactions for healthcare providers. In the first half of 2014, around one-fifth of Medical Properties Trust's total revenue stemmed from interest and fee income.

What about the stock performance? Shares are up around 12% year to date and jumped nearly 70% over the last five years. That performance, combined with a consistently high dividend yield and a relatively dependable revenue stream, makes Medical Properties Trust one of the best dividend stocks around, in my view.