Apple has redesigned the iPod line. More importantly, they’ve rethought the line based no doubt on how customers use those products. Even more relevant than leveraging the iPad, Apple has remained ahead of the competition by meeting people’s needs. And it’s strategic, as we’ll see; Apple has rocked the world of the competition, even smartphones.

Apple has sold 275 million iPods. The company plans to sell a few more. The way to do that is to avoid complacency and make sure that, despite Apples focus on the iPhone and iPad, another company or two doesn’t come along and steal the crumbs of a business. A business for which Apple might drop track. (A radar metaphor.)

You can see Apple’s thinking in the evolution of the iPods. The 3G shuffle was too abstract. Tiny buttons on the earbuds and an abstract case look cool, but customers need a minimum set of real buttons. This was very smart of Apple.

Moreover, some companies try to put a small LCD display n their smallest MP3 players. These are particularly dangerous in a car: you hear song you really like, look down, squint to see the song name … and crash! Apple’s concern for our safety with a voice only device, a shuffle, that’s perfect for use in a car, is laudable.

The iPod nano no longer supports video. My guess is that Apple was monitoring customer use with electronic monitoring of the device — still protecting customer privacy — and found that at the price point of the nano, customers weren’t interested in shooting video. Or watching movies on that tiny screen. Apple also listens well to customer feedback on the Internet. They’ve said they want to listen to FM radio while jogging. The clip on the nano is telling. People still want to wear their music, not strain their eyes.

It takes great courage to delete features from a product. Mr. Jobs has that special, minimalist philosophy, and he and his team aren’t afraid to lose a check box on someone’s comparison chart if it means a leaner, cleaner product.

Of course, I’ve mentioned elsewhere how strategic it is to have FaceTime in an iPod touch. This is Apple’s secret weapon against both the game machines and the other smartphones. This new iPod touch, contract free, has everything one needs if one isn’t into a US$2,000 commitment to a wireless contract. The iPod touch is a significant contributor to all the 120 million iOS devices Apple has sold. It makes life tough for the other smartphone makers, in terms of price points and profit margins, thanks to Apple’s iOS product volume. Apple is able to buy NAND Flash for their own products in high volume and low price, and it gets preferred treatment for NAND Flash purchases paid with cash. In a world that doesn’t pay, Apple does.

All in all, Apple has profoundly rethought the iPod product line just when some pundits, who’ve looked at the iPod as a percentage of Apple sales, predicted the demise of the iPod. This is Apple being routinely, severely aggressive, not giving an inch, and delivering more really great products. There’s no rest for the weary competitors.