So far this year, I have discussed seven stocks to buy for the year that lies ahead. Then again, fortune can go both ways. What's great for one company may be terrible for another. Yes, there are opportunities on the long side in 2006, but there are also some companies that may make for better short plays. That's why I'm going to trade in my Mr. Brightside outfit for a black robe and a sickle this time.

I don't enjoy playing the pessimist. That's why I hope I'm wrong. Six of the seven stocks that I singled out as attractive equities are beating the market, so if you happen to own one of these stocks -- or are looking to buy in -- I won't be offended (or insulted) if you email me on Dec. 31, 2006, to let me know that I blew it.

1. ExxonMobil (NYSE:XOM). Right now, the petroleum giant is the country's most valuable company. However, commanding the richest market cap isn't a permanent birthright. ExxonMobil is simply holding the baton that once belonged to GE, Microsoft, and even Cisco (NASDAQ:CSCO). That doesn't mean ExxonMobil will relinquish the throne over the next 12 months, or even that it has to decline in value to do so. However, there are a few factors working against ExxonMobil at the moment.

Over the past year, ExxonMobil rode higher fuel prices to record profits and heady stock gains. In what I consider an alarming move, five CEOs of the major gasoline companies were even brought in to testify before Congress last month. It wasn't simply a matter of defending their profitability, but that's the way their testimonies seemed to play out.

I don't think the government is going to twist screws until it regulates your corner gas pump the way states regulate their public utilities. It's just that the sentiment toward Big Oil isn't exactly favorable these days. The fundamentals aren't looking much better.

Gas prices have settled back down. However, drivers stung at the pump have turned to smaller, more fuel-efficient cars and are gobbling up hybrids as quickly as they roll off the assembly lines. Analysts still expect ExxonMobil to grow earnings by 6% next year, and I think that's going to be a big challenge for the company. The catalysts have turned.

2. Google (NASDAQ:GOOG) -- I had to wrestle with this pick, because Google is one of my favorite publicly traded companies. In fact, in a decade or two, I wouldn't be surprised to see Google's chubby fingers wrapped around the market-cap baton that ExxonMobil is currently clutching. The problem here lies in 2006. I have defended the bulk of Google's share price gains up to this point, but that's going to get a lot trickier in the near term.

Is there another $125 billion company that relies on online advertising for 99% of its revenues? No, but the reason to fret over Google isn't as simple as that. Interactive marketing is growing, and Google will continue to lead the way. The problem is that rivals are getting smarter. Yahoo! (NASDAQ:YHOO) launched a competitor to Google's brilliant AdSense that may make some third-party publishers pause before picking Google as their ad purveyor. Now, Motley Fool Inside Value recommendation Microsoft (NASDAQ:MSFT) is close to winning over AOL, Google's largest third-party publisher, and possibly beefing up its search engine with tangible rewards for loyal users.

The growing paid-search market, along with smarter competition, can play itself out in several ways. Will fraudulent clicks become a bigger issue? Will a sea of worthy alternatives make sponsors bid smarter (and lower)? Losing AOL isn't a corporate killer -- Google's been growing its organic traffic at a faster clip than its third-party network lately -- but it does give an upstart in paid search an instant sizable audience. Google's share price is built on the foregone conclusion that the company will trounce estimates, as it has in just about every quarter since going public. I think Google will make out just fine in the long term, but I see streaks of mortality creeping in as 2006 unfolds.

3. Toll Brothers (NYSE:TOL) -- This week came hogtied with the 13th straight rate hike from the Fed. It would be easy to say that the housing bubble has been burst and there will be building debris everywhere, but it's not like that. Real estate developers have had their cyclical lulls in the past, but this time around, they're well-positioned to ride out a slowdown. In other words, don't expect the homebuilders to give up all, or even most, of their huge share price gains.

That's why I'm certainly not predicting a complete collapse here. Rival developer NVR (AMEX:NVR) has been one of the five best-performing stocks over the past 11 years -- up better than 12,000% -- and it's just not going to give all of that away. More than a few companies even have healthy order backlogs to see them through over the next few quarters. The problem for developers in general -- and Toll in particular -- is where the market will be at that point. You know the drill. Rising mortgage rates give homebuyers less bang for their house-hunting buck. That keeps prices in check. Steady or falling home prices spook real estate investors and condo flippers out of the market. It's a house of cards that won't necessarily end horribly -- but it can't end well.

Toll has been the industry's biggest worrywart, sounding the loudest cautionary tone. It's contagious. Two months ago, analysts had the company earning $6.51 a share in its next fiscal year. That target is now down to $5.55 per share. Yes, it's still an attractive multiple, but the same company that has beaten projections consistently in good times may very well come up short in the lean times that most likely lie ahead.

The return of Mr. Brightside
So what's an investor to do? Well, if you've got enough foresight to find stocks due to suffer in 2006, it's not much harder to find another selection of stocks poised to thrive. We've just released Stocks 2006, an in-depth and thoroughly researched look at a dozen companies that appear ready to run higher next year.

In fact, if you've been eyeing a subscription to any of our newsletter services, like Motley Fool Hidden Gems or Motley Fool Rule Breakers, your timing couldn't be better. For a limited time, take part in any of our newsletter experiences for a year, and Stocks 2006 will be yours for free.

If you play your cards right, your pessimism may be another thing worth selling in 2006.

Longtime Fool contributor Rick Munarriz does enjoy time travel, or at least the idea of it. He does not own shares in any of the companies in this story. The Fool has a disclosure policy. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.