The Dow Jones Industrial Average this week briefly touched the 13,000 mark for the first time in years, signaling continued strength in this multiyear rally. For optimists, these rallies may seem like a dream come true. For skeptics like me, they're opportunities to see whether these companies have actually earned their current valuations.

Keep in mind that some companies do deserve their current valuations. Discount retailer TJX (NYSE: TJX) has been riding the wave of price-conscious consumers for years and just yesterday posted a 42% rise in net income as same-store sales rose 7% over the year-ago period.

Still, other companies might deserve a kick in the pants. Here's a look at three companies that could be worth selling.

Riding high on the hog
I’m sure this isn’t going to make me Mr. Popular, but it just might be time to get off the hog. Harley-Davidson (NYSE: HOG) recently reported full-year results in which the motorcycle manufacturer noted a 13% rise in sales amid rising consumer confidence. The results themselves were decent given the weak economic conditions seen around the world, but I think now might be the time to hop off this ride.

Though not expensive by historical standards, Harley-Davidson is currently trading at more than four times book value and 12 times cash flow. This may not sound like much, and if you compare it to the early 2000s, this is pretty much in line with the metrics back then. But consider that Harley-Davidson was growing much faster a decade ago than it is now. With sales growth projections of only 6% this year, it doesn’t make a lot of sense to buy into the stock, which is at multiyear highs in terms of book value and price-to-cash-flow. Add in the potential for European uncertainty and I feel you have enough question marks to park this one in the garage for a while.

This valuation needs a diet
While we’re on a valuation kick, let’s also take a closer look at nutrition and weight loss company Herbalife (NYSE: HLF). If you recall, one of my least favorite sectors out there is the nutrition and weight loss sector because consumers' fickle spending habits, business seasonality, and low customer loyalty usually quells any short-term strength in these stocks. This has been my argument against owning NutriSystem (Nasdaq: NTRI) for years and it is the primary reason the stock is down about 40% over the trailing 12 months.

Herbalife has enjoyed a recent bout of success. In its fourth-quarter report, Herbalife posted a 20% rise in sales and a 22% jump in profits and boosted its full-year 2012 outlook higher than what Wall Street had predicted. Still, just like Harley-Davidson, Herbalife is trading at multiyear highs in terms of trailing-12-month earnings (20), price-to-book (14), and price-to-cash flow (15). I simply don’t trust the brand loyalty of consumers in this sector and think it would be prudent to avoid the stock at these levels.

Twilight or sunset?
2011 was not a particularly strong year for movie sales. Total ticket sales fell for a second consecutive year, and 2012 hasn’t started off strong either, with sales currently on pace to drop for a third year in a row. This bodes particularly poorly for Lions Gate Entertainment (NYSE: LGF), which has only had four profitable years in the past 10.

Lions Gate is expecting to at least return to profitability in 2012, thanks to the release of another movie in the Twilight series. But can you really trust the stock beyond just one major title? I certainly can’t -- especially at 42 times book value. Outside of digital and on-demand revenue, Lions Gate’s third-quarter results echoed the string of continued yearly losses. Until Lions Gate can consistently produce profitable quarters, I’d leave this curtain closed.

Foolish roundup
As the market indexes continue their march higher, valuation is becoming more and more important. These three stocks simply don’t have the earnings potential to match their valuation and look like excellent sell candidates. I'm so confident in my three calls that I plan to make a CAPScall of underperform on each one. The question now is: Would you do the same?

Share your thoughts in the comments section below and consider using the links below to add these three stocks to your free and personalized watchlist so you can keep track of the latest news with each company. Also, to avoid investing in stocks like these, consider getting a copy of our special report "The Motley Fool's Top Stock for 2012." In this report, our chief investment officer details a play he dubbed the "Costco of Latin America." Best of all, this report is free for a limited time, so don't miss out!

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. He is fully aware that he’d be way too dangerous on a motorcycle. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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 that never needs to be sold short.