While the typical biotech company burns a lot of cash with little to show for it, Genzyme stands out for inventing so many successful drugs that it now has $4.6 billion in annual revenue, nearly $1 billion in annual cash flow and nearly $1 billion in cash.

Besides its knack for innovation and smart acquisitions, the Cambridge, Mass., company has led the biotech pack for several additional reasons. First, Genzyme specializes in developing drugs for treatment of rare diseases. Because it's typically the only company with a treatment for a given problem, it can charge a lot, and insurance companies will pay up. Its drug Cerezyme, which treats the genetic ailment Gaucher's disease, for example, was used by roughly 5,400 patients last year. But Cerezyme sales topped $1.2 billion.

Next, instead of mixing chemicals together, Genzyme produces drug therapies through a complex process known as biologics -- combining live organisms to brew up a drug. Because the process is so complex and because Genzyme's niche products serve small markets, it's tough for competitors to break in, says Jordan Schreiber, a biotech sector expert at Princeton Capital Management.

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Genzyme did misstep earlier this year when a virus infected the manufacturing process at its plant in Allston, Mass. The bad news hit Genzyme stock hard in February. Despite the trouble, over the past year the stock has outperformed Biotech HOLDRs, the exchange-traded fund tracking the industry -- cementing Genzyme's status as a recession survivor in biotech.

Morgan Stanley analyst Sapna Srivastava thinks the manufacturing issue will be resolved in the coming weeks and will have little long-term impact. That suggests Genzyme is a great buy here, especially given the number of new drugs in the pipeline. "We think Genzyme's long-term growth prospects look particularly strong," Morningstar analyst Karen Andersen says.

Continued: Amazon's sales keep climbing