If Howard Stern is "the king of all media," does that make Sirius Satellite Radio (NASDAQ:SIRI) the king of all media stocks? Yes, we know folks can get pretty rabid when it comes to Sirius. Bears think it's outrageous that such a young, profitless company can command a $7.5 billion market cap. Bulls feel that the potential of satellite radio in general -- and Sirius in particular -- makes the stock a bargain even at today's prices.

Sirius and XM Satellite Radio (NASDAQ:XMSR) make up this intriguing duopoly. They now combine for more than 9 million subscribers, and they're attracting on-air talent as quickly as they're drawing in new listeners. This doesn't mean that satellite radio is without competition, given the popularity of other ear-feeders like podcasting and portable streaming services from companies like Napster (NASDAQ:NAPS) and RealNetworks (NASDAQ:RNWK).

Satellite radio's rise has been strictly a North American phenomenon; WorldSpace (NASDAQ:WRSP) shares have yet to gain traction as a satellite radio provider overseas.

The battle between Sirius and XM -- a Rule Breakers newsletter recommendation -- is an interesting one, but so is the battle over Sirius's merits as an investment. Is Sirius ready to rock the market? Not all Fools agree. Rick Munarriz feels the heady growth and uncharted upside is worth celebrating; Alyce Lomax argues that the stock is overpriced, given its financial state and its relative valuation to the larger XM.

Does Sirius Satellite Radio belong in your portfolio? That's what this week's Duel is all about.

Duel on!