The house rules are simple in this weekly column: I bash a stock that I think is heading lower, then offset the sting by recommending three stocks as portfolio replacements.

Who gets tossed out this week? Come on down, Apple (Nasdaq: AAPL).

An Apple a day helps keep the bears away
This one's going to hurt. I'm a huge fan of nearly all things Apple, and I routinely turn to the class of Cupertino in this column as one of the three replacements. However, something has troubled me at Apple over the past few trading days -- and I just can't ignore it.

We all knew that Steve Jobs' health was a delicate issue, but his abrupt resignation last week still shocked me. Apple shares took a swift hit in after-hours trading on the news, but with most analysts arguing that this was a buying opportunity, Apple's stock shed less than 1% the following trading day. A week later, it's a brisk jog away from an all-time high.

The market overreacts sometimes. Stocks get pummeled on slight misses or guidance tweaks. You routinely see a company make a questionable acquisition, only to shed more in market cap than it paid for the actual deal. But this time, Wall Street's clearly underreacting.

Do you think that shares of Oracle (Nasdaq: ORCL) or Berkshire Hathaway (NYSE: BRK-A) (NYSE: BRK-B) would trade 2% higher a week after Larry Ellison or Warren Buffett headed for the door? Of course not. Ellison is the master architect of Oracle's acquisitive strategy in enterprise software. And I don't want Buffetteers arguing that Charlie Munger is as good as Buffett, because we just don't know how well one would perform without the other. Besides, Munger's no spring chicken, either.

As Apple's charismatic co-founder, Jobs is irreplaceable. I don't buy the argument that Jobs' departure was priced in. Jobs got us to buy tablets -- not because they were practical, but because they were magical. Who will sell us on Apple televisions in 2012, cars in 2017, and teleportation pads in 2022? Jobs was the salt-and-pepper scruffy face of Apple. We'll continue to buy iPhones and MacBooks, but will the local Apple store still be as cool?

Shares of Apple look cheap relative to its recent growth. It's hard to talk investors away from the allure of Apple at 14 times this fiscal year's projected profitability, and a mere 12 times next year's target. However, Apple will face challenges without Jobs. It's more vulnerable now than it was a resignation ago.

Can anyone now guarantee that Apple will be more relevant five years from now than it is today? I felt that way before. Now that a company reliant on selling premium hardware is missing its salesman, I'm not so sure.

Good news
As I do every week, I don't talk down a stock unless I have three alternatives that I believe will outperform the company getting the heave-ho. Let's go over the three fill-ins.

Google (Nasdaq: GOOG)
The world's leading search engine remains a handful for Apple on the iPhone front. Android devices keep padding their market-share lead in this country. It's true that Apple doesn't see this as an arms race. It's commanding formidable profits, while Google gives its platform away as a lifeboat to non-Apple handset manufacturers. However, Google's ability to finally make an open-source solution marketable will eventually eat into Apple's smartphones, tablets, and even computers. As it stands, Google also trades at a compelling discount to its growth rate, fetching less than 13 times next year's bottom-line estimates.

Amazon.com (Nasdaq: AMZN)
For months, I've been saying that the only thing that Apple needs to fear on the iPad front -- for now -- is Amazon. The leading online retailer is now just weeks away, reportedly, from introducing the first of two tablets. Why can Amazon succeed in areas where other "iPad killers" have failed? Well, Amazon has an ecosystem of digital products to push, so it can afford to sell its tablets at cost -- or even at a loss. We've seen Amazon's aggressive pricing strategy with the Kindle, slashing the gizmo's price by roughly two-thirds since it hit the market just four years ago. The e-tail giant will likely make these tablets stick.

Amazon also offers video streaming of select titles -- at no additional cost -- to its millions of Prime loyalty shopping club members. This will be a major differentiator. I won't insult you by bringing up Amazon's valuation relative to Apple and Google. It's not cheap, but it's also never been cheap.

ZAGG (Nasdaq: ZAGG)
There is pride in being a bandwagon hopper. ZAGG's popularity exists largely thanks to its ability to sell screen protectors and other third-party accessories for Apple products. Revenue soared 158% in its latest quarter, blowing past Wall Street's profit targets along the way. I like ZAGG here because it's not just a pure play on Apple. ZAGG also makes protective and enhancing accessories for other touch-based smartphones and tablets. As the market widens for opportunities outside of Apple, ZAGG should be able to outpace Apple's growth.

I hope I'm wrong about Apple, but I don't think life will be so easy post-Jobs.

The Motley Fool owns shares of Oracle, Google, Berkshire Hathaway, and Apple. Motley Fool newsletter services have recommended buying shares of Berkshire Hathaway, Google, Amazon.com, and Apple. Motley Fool newsletter services have recommended creating a bull call spread position in Apple. 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.

Longtime Fool contributor Rick Munarriz calls them as he sees them. Hedoes not own shares in any of the stocks in this story. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.