This article is part of our Rising Star Portfolios series.

It's the new year and time to lose weight, stop smoking, and buy stocks. Our Rising Stars took the last resolution to heart by purchasing 10 stocks this week for their portfolios. Yes, 10. I've provided summaries of their buy recommendations below.

Rising Star buy: Apple
Surely, Apple (Nasdaq: AAPL) can't go any higher, especially after rising another 53% in 2010. Right?

Wrong, according to Rising Star Eric Bleeker, who makes a very compelling case for Apple having "plenty of room left to run." He expects to see robust growth in sales of iPhones and iPads with overall sales for the company of $89 billion in calendar 2011, up from $65 billion today. Ultimately, Eric concludes that "everyone is underestimating Apple." I must admit that I'm convinced, but then again, I'm an Apple shareholder myself. Read Eric's complete piece and let us know what you think.

Rising Star buy: cheap defense stocks
I've got two words for you: defense stocks. OK, so that's not how Rising Star Anand Chokkavelu led off his article on defense stocks, but he did say that "when a sector gets beaten down and nothing has fundamentally changed, I get really interested."

Anand argues that the defense sector is oversold as a result of investors overreacting to the potential extent of cuts to national defense. Does anyone truly believe that the days of bloated defense budgets are over? Really?

So, Anand recommends buying a basket of the following stocks: General Dynamics (NYSE: GD), Lockheed Martin (NYSE: LMT), Northrop Grumman (NYSE: NOC), Raytheon (NYSE: RTN), and L-3 Communications. Read his article to learn more about his thinking.

Rising Star buy: GulfMark Offshore
Rising Star Jason Moser recommends buying GulfMark Offshore (NYSE: GLF), a provider of marine services to companies involved in the exploration and production of oil and natural gas. Jason likes oil and natural gas for the long term and thinks this small cap is the way for him "to play on that outlook." For more on this interesting idea, read the article.

Rising Star buy: Western Digital
Rising Star Jim Mueller bought shares of Western Digital, a leader in the hard disk drive market, for his Messed-Up Expectations portfolio. Despite having a relatively strong balance sheet and reasonable growth prospects, this company is "being priced by the market with very little growth expected." Read Jim's article to hear more about his investing thesis.

Rising Star buy: two tech stocks for 2011
Finally, Eric Bleeker purchased two additional tech stocks for his "Bits Portfolio." The companies -- EMC (NYSE: EMC) and Qualcomm (Nasdaq: QCOM) -- are "both leaders in their respective fields," according to Eric. And he believes that "each company is poised for continuing gains in 2011 that should surpass already lofty expectations." For more, read Eric's complete case.

Day one investors
Just this Wednesday, I was very fortunate to have the chance to talk with David Einhorn about financial reform, stocks, and investing in general. He told me that his company doesn't hesitate to invest in "day one investors" as part of its Greenlight Masters program. Day one investors are investment managers without track records, and I like to think of our Rising Stars in that way. Sometimes you need to take a chance on discovering greatness. Come join us and follow along with a couple of our investors. Who knows what you'll discover!

This article is part of our Rising Star Portfolios series, where we give some of our most promising stock analysts cold, hard cash to manage on the Fool's behalf. We'd like you to track our performance and benefit from these real-money, real-time free stock picks. See all of our Rising Star analysts (and their portfolios).

John Reeves owns shares of Apple. It's the first cult he's ever belonged to, and he's enjoying it immensely. The Fool has written puts on Apple, which is a Motley Fool Stock Advisor recommendation. The Fool owns shares of all of the stocks mentioned in this article. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.