I'm a sucker for a well-made TV ad.

Inspired by the Nike (NKE) "Just Do It" and "Air Jordan" campaigns of decades past, I mentally mapped out storyboards of the spots I wanted to produce. Nowadays I laugh at clever beer and soda commercials and get mad or pump my fist in the air along with political ads.

I cheered for Apple's (AAPL) 1997 "Think Different" spot that featured actor Richard Dreyfuss reading the "Here's to the Crazy Ones" speech. The commercial resonated in a house full of Mac users at a time when Macs were widely considered an endangered species. Apple's more recent "Mac vs. PC" ads lampooning Microsoft (MSFT) strike a different chord: Macs are friendly, cool, easy to use, and they don't have the kinds of problems usually associated with Microsoft's Windows operating system; PC, portrayed by the hilarious John Hodgman, comes across as ridiculous -- not unlike the real-world, buggy Windows Vista.

Now Microsoft is fighting back with its own advertising campaign. I've enjoyed some of its elements. The Seinfeld spots were weird. I was intrigued by some of the "I'm a PC" spots that aired last fall, depicting PC users engaged in a variety of jobs -- teaching law, protecting endangered species, blogging for Barack Obama. The message: You can use a Windows PC and still do cool and interesting things. Not bad. Then came the adorable little girls: Kylie, age 4, and Alexa, age 7, e-mailing pictures of fish and stitching together pictures of a fort into one. Microsoft, it seemed, had finally found its advertising voice.

Then came Lauren, the perky, red-haired twentysomething meant to represent an average American shopping for a computer. She wants a notebook with a 17-in. screen, and if she finds it for less than $1,000, she can keep it. Following her as she shops, we learn she considers the Mac too expensive -- that she's not "cool enough to be a Mac person," she whines. From the Apple store, it's off to Best Buy (BBY), where she finds a PC that meets her specifications for $699. Mission accomplished, she jumps up and down clapping as though she won on The Price Is Right, ending the spot by saying "I'm a PC, and I got just what I wanted." Aaaand Cut!

The Price Weapon Microsoft used earlier ads to defend itself suitably against Apple's nerdiness allegations. Now Microsoft is on the advertising offensive, wielding price as a weapon of choice. It's an effective approach during a recession. But as is always the case with advertising, the full story is more nuanced.

Yes, $699 beats the $2,800 you'd pay for a Mac with a 17-in. screen. But when it comes to PCs, there's still a great deal more to buy.

First, there's security software.