I really didn't want to write this article. Hopefully, it won't come back to bite me -- but if it does, I hope you profit from it!

You see, I'm pretty regimented about making monthly contributions to my Roth IRA and having that act as the bulk of my investing. But after cutting back on some expenses, my wife and I have a little more to invest than we usually do.

As it is, I thought it was worth waiting for deals to appear before investing that extra money. But those deals, in my humble opinion, have appeared. And because I write for the Motley Fool, I'm going to have to wait two long, excruciating days before I can consider buying the three stocks I'm going to reveal.

Below are the companies that have my mouth watering right now, and at the end I'll offer you a special free report on five stocks investors need to keep an eye on this earnings season.

Westport Innovations (Nasdaq: WPRT)
I'll be the first to admit it: Westport's stock had probably been asking for a correction. It's hard for investors to keep bidding up a company that has yet to turn a profit -- especially when it's already up 80% over the past two years.

And sure enough, the company -- which designs engines that can run on natural gas -- has been hit hard. Since hitting a high of $50.19 in late March, it has lost a third of its value. And Westport isn't alone: Fellow natural-gas play Clean Energy Fuels (Nasdaq: CLNE) -- which is building out a network of natural-gas refueling stations -- is down about 25% since hitting its high on the same day Westport accomplished its feat.

Record low natural-gas prices, as well as a string of encouraging announcements within the industry, helped propel these stocks. It could be that momentum investors are simply locking in their gains. Or maybe people want to see profitability before paying any more for these two.

Either way, for the long-term investor, there's an opportunity waiting. While some are concerned about fellow engine maker Cummins (NYSE: CMI) developing its own 15-liter natural-gas engine, those concerns are overblown. The engine won't have near the torque of Westport's high-pressure, direct-injection version.

Though Westport shares could easily continue falling, I think any price under $40 will look like a steal five years from now.

IPG Photonics (Nasdaq: IPGP)
If you've invested in IPG over the past year, you know what a roller-coaster it has been.

It's all pretty easy to understand. IPG makes industrial-strength lasers -- the kind used to help make cars and heavy machinery. If investors think industrial output will rise, then demand for IPG's laser will rise, as well as its stock price. With every whisper of a global slowdown, however, the stock's price takes a swift kick to the gut.

But there's a catch: IPG is the first-mover and top dog in fiber-optic lasers. These lasers are becoming far more powerful than their carbon-based peers, and their design is easier to use and more reliable. Because the company is fully integrated, it can suffer during downturns.

But if you believe -- as I do -- that the larger economy will continue improving over the next decade, IPG will be a surefire winner.

Apple (Nasdaq: AAPL)
Finally, we come to the world's most valuable company. Yes, shares are up over 40% on the year -- but you have to consider the ridiculously low price they were starting from. Almost as a rule, when a company's stock price goes up, an appreciation in the company's price-to-earnings ratio accounts a good chunk of the rising value. But if you look below, Apple's price for most of the past two years has risen in spite of its P/E.

Source: E*Trade. Blue represents share price. Purple line represents trailing P/E.

The stock, though, is down about 10% in just the past week. Recently, NYU Business School professor Aswath Damodaran laid down his reasoning for selling Apple -- which he initially bought in April 1997.

Damodaran doesn't think the company is overvalued, nor does he think the company's decision to institute a dividend is a sign that it's growth days are over. Rather, he doesn't like the company he's keeping in his fellow shareholders -- a mix of dividend investors, momentum players, and big institutions.

Those are fair concerns, but if the company continues to execute is strategy, the stock is likely to be trading higher years from now than it is right now.

Don't miss this opportunity
I've already backed up my pick on my All-Star CAPS profile -- and with my own money. While it's important to take your time before making investing decisions, sometimes the window of opportunity isn't that big.

With earnings season just getting started, one such opportunity to strike is presenting itself. We've put together a special guide to prepare you that will only be available for a short time: "5 Stocks Investors Need To Watch This Earnings Season."

Inside you'll get the scoop on all five of these companies -- and I'll even give you a head start by telling you that two of the companies were discussed in this article. Get your report today to find out which ones are covered, absolutely free!