If you think that Sirius (NASDAQ:SIRI) is some uproariously hilarious investment fit only for market simpletons, the joke is on you.

Oh, I know. You think that you're one step ahead of those plunking down their money on some money-losing satellite radio upstart. When someone buys into Sirius because the share price is so cheap, you chuckle because you know that each of those shares represents one of 1.3 billion lottery tickets in what has to be a hoot of a sucker bet. A $9 billion company can't be cheap.

When someone buys into Sirius claiming that Howard Stern is the King of All Media or that the company's revenues grew fivefold last year, you snicker. You can divide that $9 billion market cap into the $67 million that the company generated in revenue last year. Or the $712 million that it lost. Or the $500 million that it will shell out for five years of King Stern.

Keep laughing. I believe in Sirius. And I believe in the stock for some legitimate reasons. I'm not about to volley up the perfect punch line spike for you. Or for my bearish bud Rich Smith. So let out the guffaw that you've been packing. It may be your last.

It's an inside joke. Only you're the one on the outside looking in.

Sirius is looking to close out the year with just 2.7 million subscribers. That's less than half of the 5.5 million radioheads that rival XM Satellite Radio (NASDAQ:XMSR) is angling to serve by then. Why should Sirius be valued higher than XM's $7.5 billion price tag?

It's simple, really. Sirius is so cool that XM wants to be Sirius. The $12.95 monthly price. The free online streams for subscribers. The digital free music channels. The big money pro sports contracts. XM has aped Sirius on all of those fronts. Last month, Sirius announced that it had developed a proprietary technology that would allow it to expand its programming channels by 25%. XM followed in July by acquiring a wireless company rich in spectrum licenses.

Stern arrives come 2006 and Sirius, once at a major disadvantage to XM due to the number of auto factory installs that XM had lined up, has caught up in a hurry. Between the NFL in the fourth quarter and Stern in the quarter that follows, I would be shocked if Sirius isn't the one signing up more new subscribers at that point.

But I hate to make this a Sirius vs. XM thing. I am bullish on both companies. That's because as exorbitant as $16.5 billion may seem for both companies, DirecTV (NYSE:DTV) and EchoStar (NASDAQ:DISH) combine for $35.5 billion in market cap. Sure, these are established satellite television providers. Yes, folks are willing to pay more for televised broadcasts than audio ones. Then again, steep deficits haven't held the satellite television companies back. They also have to duke it out against the brass-knuckled fists of digital cable providers. Sirius and XM? The premium domestic radio market is all theirs, man.

That's why free radio stars like Stern and Cousin Brucie -- along with celebrity voices like Lance Armstrong, Eminem, and Martha Stewart Omnimedia's (NYSE:MSO) own Martha Stewart -- are all migrating to Sirius. And because XM and Sirius are starting to differentiate their content, we aren't too far away from a time when the ideal satellite radio subscription will be to both providers. That's why the potential market is far greater than most people think.

Sirius has already partnered with Microsoft (NASDAQ:MSFT) to develop video stream broadcasting. No, it won't replace your present tube preferences, but can you imagine having fresh cartoons to play in the minivan through your car's backseat monitor to keep the kids entertained during that next road trip?

That's just one of the many ways that both Sirius and XM will be able to cash in on their growing audience. The red ink at the moment appears daunting, but that's only because so much of Sirius' overhead is fixed. That will play into the company's financial scalability as it goes on to sign up 10 million, 20 million -- or more -- avid listeners over the years to come.

Analysts expect losses to narrow slightly next year on revenue of roughly $530 million. That implies that the top line will have grown eightfold in a span of just two years.

So keep laughing. Keep believing that Sirius is to investing what Manos: Hands of Fate is to cinema. If you don't think that Sirius will be a much more important -- and valuable -- company five or 10 years from now, I have some advice for you. Lose the earplugs.

You're not done. This is just one part of a four-part Duel! Don't miss the Bear argument and the Bull and Bear rebuttals. When you're done, vote and let us know who you think won this Duel. If you appreciate ultimate growth stock investing -- in companies just like Sirius -- you may want to give our Motley Fool Rule Breakers newsletter service a try.

Longtime Fool contributor Rick Munarriz is a Sirius subscriber, but he doesn't own any shares mentioned in this duel. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy .