What companies are tomorrow's big winners? In our ongoing series, I'm chatting with Fool analysts and advisors to discover the stocks they're watching, and the catalysts that would signal a time to buy.

Today, Motley Fool analyst Joe Tenebruso shares two companies on his watchlist, and one that he's loading up on now. (For your convenience, you can now create your own version at MyWatchlist.com, your free customized hub to follow the performance and Fool coverage of the companies you care about.)

In the world of search, Baidu.com (Nasdaq: BIDU) owns China and Google (Nasdaq: GOOG) rules the rest of the world. Those enviable positions are reflected in their share prices, since neither is exactly flying under the market's radar. But Joe feels both have more room to run than market sentiment indicates. First, it's looking increasingly unlikely that a rival will be able to shove Google from its perch as search leader. Its Android success has allowed it to capitalize on the fast-growing trend in mobile communications, and it's showing signs of additional innovation expansions. "There's not a whole lot of room for Google to pick up market share in search, but it'll still see growth as the industry expands," says Joe. "And once people start seeing more diversified revenue streams, I think that will fuel even higher share prices."

Baidu.com hasn't necessarily shown the agility of Google nor the willingness to branch out from its core competencies in search. But especially since Google left the Chinese mainland, Baidu has built what seems to be an unassailable advantage over its competition. "Baidu doesn't have to do anything except maintain its lead in China," Joe says. "The Chinese market is growing phenomenally, so it doesn't need to increase market share or diversify. If it can hang onto its spot, it's in a great position."

Joe is watching shares of both search providers for pullbacks in price.

And one he bought
He's also waiting for a buying opportunity to go back for more on Apple (Nasdaq: AAPL), which already accounts for the largest position in his portfolio. He's enamored with the company's products, its pristine balance sheet, and its prospects.

"It's one of the largest companies in the world, yet it still has the growth rate of a small cap," says Joe. He feels Apple still has plenty of opportunity to capture market share, especially if it goes through with the long-rumored deal with Verizon (NYSE: VZ), which would dramatically expand its appeal and potential. A lot of people were willing to give up their Verizon contracts in order to get an iPhone, but an order of magnitude more decided to wait for Apple to open up its network options. Joe plans to make a purchase if and when Apple shares drop back to $300, and he's confident they can climb to $400, especially if a Verizon deal happens early in 2011.

And that's why it pays to watch. You can make smarter investing decisions with your own version of My Watchlist, new and free from the Fool. Click below to start following one of the stocks mentioned above:

Roger Friedman doesn't own shares of any companies mentioned, but they're all now on his watchlist. Google is a Motley Fool Inside Value recommendation. Baidu and Google are Motley Fool Rule Breakers picks. Apple is a Motley Fool Stock Advisor choice. The Fool owns shares of Apple and Google. 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.