Apple Computer's ( AAPL) first-quarter earnings announcement later Wednesday may be lacking in drama, but it certainly won't be without an audience.

CEO Steve Jobs already announced many of the headline numbers, including revenue and number of Macintosh computers and iPods shipped , at last week's Macworld conference. But investors will still be scrutinizing the earnings announcement to get a sense of where the company will go next.

Although there's eagerness to hear actual financial guidance, other items may draw as much or more interest from investors. Among them: the company's operating margin in the just-completed quarter, any word on its retail store build-out , and any hints of new products to come.

"The fundamental momentum of this company is becoming more secure, so the guidance may have less impact on investor sentiment than it has in the past," says Tony Ursillo, a buy-side analyst at Loomis Sayles & Co., which holds Apple shares.

As revenue has ballooned over the last two years, so too has the company's operating margin. Ursillo and other investors will be looking to see if that trend continued in the fourth quarter, when the company's sales significantly overshot its revenue guidance and the Street's expectations.

Much of Apple's stock and financial rebound has been driven by the iPod and its investment in retail stores. Analysts will be looking to see if the company has a hit new product up its sleeve that might succeed the iPod as a growth driver. They'll also be looking to see just how big the company's retail chain can get.

"Not to take anything away from the iPod or the iPod nano -- those are hot products that deserve to get attention -- but the one thing we think is underappreciated by the Street is Apple's retail stores," says Dave Bujnowski of Coburn Ventures, a consulting firm. "Any comment they have on whether it's going to be 160 stores by end of year -- or 170 -- that's what I'm going to be interested in," adds Bujnowski, who manages a mock portfolio in which Apple is one of the top holdings.

To view a video preview of Wednesday's call, click here .

This focus on the future is to be expected, given Apple's current valuation -- and the expectations the company has raised among its fans. Particularly with the iPod line, the company has delivered a series of hot products in recent years that have dominated the market. With the stock now trading at 39 times expected current-year earnings, the Street clearly believes the company will continue to deliver winners.

Investors' optimism seems only to have gone up in recent days. Since Jobs pre-announced the company's holiday-quarter results, Apple's shares have risen 11%.

Certainly, investors had a lot to cheer about. Apple posted $5.7 billion in sales in its fiscal first quarter, Jobs said. That not only represents 63% growth, but it's $1 billion more in sales than Apple had predicted and about 13% more than the Street had forecast.

That gaudy revenue figure was driven by surging iPod sales. Apple sold 14 million of the digital music players in the quarter, which was at the top end of analysts' estimates and more than double the number the company shipped in its previous quarter, sequentially.

The main figure Jobs left up to the imagination was actual earnings. Investors said they weren't all that concerned with the profit number itself so much as what happened with Apple's operating expenses in the quarter.

With Apple controlling costs, the company's operating margin has gone from being a loss representing about 2.5% of sales in the first quarter of the company's 2003 fiscal year to 12.4% of sales in the second quarter last year. However, the company's spending on research and development, and marketing and administrative expenses have creeped up in recent quarters, so that operating margin stood at 11.4% last quarter.

Even with the company's blowout quarter on the top line, margin could possibly have taken another hit. While Apple saw strong iPod sales, sales of its Macintosh computers grew at a far slower rate and came in lower than analysts were expecting. Analysts generally believe that Apple sees higher gross margins on its computers, meaning that if the iPods contributed a greater portion of total revenue than in the past, the company's gross margin would decline.

Strong iPod demand might have had another dampening effect on gross margins: With demand outpacing supply, Apple might well have resorted to expensive means to rush production or delivery of iPods to customers, Ursillo warns.

But the bigger question is how much of the revenue windfall Apple decided to let pass through to the bottom line, vs. devoting to advertising or to product development, he says.

"I'm curious to see what sort of leverage a quarter like this creates for Apple," he says.

If Ursillo is focusing on what Apple can do on the bottom line, other investors are focusing on what the company can do to continue to boost its top line.

Apple's retail stores took in a billion dollars in sales in the fourth quarter, Jobs announced last week. That's up from $561 million through the retail stores in the same period a year earlier.

But it's not just gross sales that are going up, it's also sales per store, notes Bujnowski. The average Apple store posted $5.6 million in sales in the 2004 holiday quarter and $7.4 million in the just-completed holiday period. That's a strong indication that although store count is going up -- to 135 at last count -- Apple is nowhere near saturating the market, says Bujnowski. Now the key question is how many more stores the company believes it can open, because those new stores will likely drive higher sales, he says.

"We look at the retail stores not just as buzz generators," he says. "The stores have a lot more earnings power than people think."

Last but not least, there's the product pipeline. To some fans, Macworld was a disappointment. While Apple did launch early some new computers that will incorporate processors from Intel ( INTC), many analysts had seen that coming. Meanwhile, despite rumors circulating about all kinds of new gadgets in development, the company didn't unveil any totally new product or announce any flashy new iPod updates.

That's left many analysts and fans eagerly awaiting word on what's to come. And while few really expect to hear something on an earnings call, there's always hope.

"People are looking for more announcements," says Jim Grossman, a portfolio manager at Thrivent, which is long Apple. "I think people would even like to have an announcement of another announcement."