Here's an interesting tidbit from Mark Hulbert, whose Hulbert Financial Digest has been tracking the financial newsletter industry since 1980. In a column for MarketWatch, Hulbert says Apple (NASDAQ:AAPL) is the most recommended stock among the roughly 200 advisors he tracks.

If all this Apple love worries you, Hulbert says, you could consider other stocks in the same industry that are also popular with newsletter advisors, including Hewlett-Packard (NYSE:HPQ) and Western Digital (NYSE:WDC).

Most loyal Fools know that David Gardner has recommended Apple for his Motley Fool Stock Advisor members. David was in before the stock hit the top of the leaderboard, and his pick is beating the market by 38 percentage points since the original January 2008 recommendation.

Now that Apple is the top banana among newsletter advisors, is its upside limited? It's an intriguing question, and I'd be interested in your comments below.

Rex Moore has calculated pie out to 12 slices, but owns no shares of Apple or any other company mentioned here. Apple is a Motley Fool Stock Advisor pick. The Motley Fool has a disclosure policy.