We aren't even out of winter yet, but the flip-flops are out in full force, with the broad-based S&P 500 (SNPINDEX:^GSPC) swinging significantly lower at the open immediately following a big up day and decisively higher immediately after a big down day.

What little economic news we did get was positive, with the Mortgage Brokers Association noting that mortgage applications filed last week rose a robust 16%. Low interest rates and a thinning number of available homes are suddenly driving prospective homebuyers to take the plunge.

Earnings also continue to be a major driver of the markets, with a mixed bag of reports sending the S&P 500 to a rather boring finish. For the day, the S&P 500 was fractionally higher by just 0.83 points (0.05%) to close at 1,512.12. Although the close might seem tame near the flat line, there were quite a few big movers within the S&P 500. Here's a quick glimpse at three of today's best stocks.

Solar panel maker First Solar (NASDAQ:FSLR) shined the brightest of all 500 companies today, rising more than 7% after Citigroup initiated coverage on the company with a buy rating and a price target of $41. Specifically, Shahriar Pourreza, the covering analyst, notes that First Solar's strong balance sheet and knack for landing big projects should keep its growth prospects robust for many years.

However, First Solar wasn't the only company praised by Pourreza. In fact, four of the seven companies he examined in the solar sector were initiated with buy ratings, including SunPower (NASDAQ:SPWR), a current outperform CAPScall in the TMFYoungGuns portfolio, which Pourreza listed as a "conviction list buy" and noted its industry-leading efficiency and financial backing from Total as reasons for the call. I would, personally, much rather own the efficiency leader in SunPower, which has just as many quality joint ventures as First Solar and comes with a much more reasonable valuation.

Chipotle Mexican Grill (NYSE:CMG) chimed in with a strong day as well, advancing 5.7%, after reporting its fourth-quarter results. The Fresh Mex chain reported a 7% increase in net income to $61.4 million as revenue rose 17% to $699.2 million. Both figures were more or less in line with Wall Street's expectations. More importantly, same-store sales rose 3.8%, lower than in years past but a bit higher than some had expected. Unfortunately, Chipotle predicts that rising costs will keep hampering its bottom line, but it remains cautious about increasing prices in a weak economy and sending its customers elsewhere. I'm standing by my original assessment and avoiding Chipotle for the time being.

Finally, the unstoppable Netflix (NASDAQ:NFLX) joins the crowd by logging yet another $10, or 5.8%, gain. Helping the in-home streaming content king out today is news from the U.S. Postal Service that it will soon stop Saturday mail deliveries, which will ultimately cut down on Netflix's shipping expenses and might even coax more DVD users to transfer over to streaming videos. This comes on the heels of a very big earnings beat two weeks ago and a key content deal announced with Disney just two months ago. Everything appears to be going Netflix's way at the moment, but I still have my doubts about the company's long-term success.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. 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.

The Motley Fool owns shares of Citigroup, Chipotle Mexican Grill, Netflix, and Disney. Motley Fool newsletter services have recommended buying shares of Total, Chipotle Mexican Grill, Netflix, and Disney. 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.