These days, the iPhone and iPad are Apple's bread and butter. But before they arrived on the scene to help Apple become the largest technology company in the world, the iPod was the shining star.

The original iPod was released exactly 15 years ago on Oct. 23, 2001. Steve Jobs's pitch was simple: 1,000 digital songs in a sleek device about the size of a deck of cards.

Then with the iTunes Store, Apple revolutionized and legitimized music downloads. As the iPod grew more popular and opened up to support Windows, Apple added more models (Nano, Shuffle and Touch). The rest is history.

Apple still makes and sells iPods, but they're not prominently advertised like they once were. You'll find them in a very small section at Apple stores and shuffled under the "Music" section on Apple's website.

In honor of the iPod's 15th birthday, we've rounded up the most notable iPod designs of all time. First, our picks for the best iPods throughout the years.

iPod

Love it or hate it, we owe a lot to the original iPod. Its chunky design may not hold up quite as well today, but without it, there would have been no iPod nano or iPod touch or iPhone or iPad. Apple's iOS devices owe their existence to the original iPod.

iPod mini (1st and 2nd-gen), 2004

Before there was an iPod nano there was the iPod mini. The iPod mini shrank the iPod down to a smaller form factor, introduced the integrated click wheel with playback buttons that we all know and love, and introduced different colors. This was the beginning of Apple infusing style into its devices.

iPod touch (1st-gen), 2007

The original iPod touch transitioned the iPod into a post-iPhone world. Released on Sept. 5, 2007, the iPod touch (often called the "iTouch" by fans) was essentially a thinner, sleeker original iPhone sans camera and cellular connectivity.

The iPod touch was the first iPod with a touchscreen and Wi-Fi. The App Store later would turn it into a formidable gaming device.

iPod video (5th-gen), 2005

Video. On. Your. iPod. In 2005, that was a very, very big deal. This iPod also had a thinner and lighter design. In addition to the 30GB and 60GB models the previous fourth-gen iPod classic came in, Apple also added an 80GB model. It would eventually be succeed by the (now discontinued) sixth-gen iPod classic with up to 160GB of storage.

iPod nano (2nd gen), 2006

The original iPod nano was nice, but it had a few shortcomings. Namely, it started at 1GB, it scratched really easily and only came in black or white. The second-gen iPod nano came in 7 colors, had a more durable aluminum case and started with twice as much storage. It was like a super-thin iPod mini.

iPod nano (6th gen), 2010

Compared to its predecessor, the sixth-gen iPod nano was a huge departure. It dumped the click wheel, widescreen (video support) include in favor of a square touchscreen with the iPod shuffle's clip-like design.

Many disliked its regression in design, but it was notable because it was a precursor to the Apple Watch of sorts. There were a number of third-party companies that sold watch bands and housing enclosures that turned it into a watch.

And now for what we think are the worst iPods created...

iPod Shuffle (1st-gen), 2005

The original iPod shuffle was introduced as the most inexpensive iPod ever. It lacked a screen and instead of a click wheel had simple playback controls. It came with a dorky lanyard so you could wear it around your neck -- and you could only listen to your music on shuffle. Can you even imagine?

iPod Shuffle (3rd-gen), 2009

The third-gen iPod Shuffle is easily one of the most forgotten iPods. The design was sleek, but with no physical controls -- you used the inline remote on the included earbuds or VoiceOver -- the device was a huge step back from the second-generation model.

iPod classic (3rd gen), 2003

The third-gen iPod classic was the only iPod with four capacitive playback buttons above its wheel (which wasn't clickable yet). Having to lift your thumb off the click wheel to access the buttons was just plain weird. It's no surprise Apple didn't bring this odd design to any other iPods.

iPod nano (3rd-gen), 2007

Like a miniaturized iPod video, the third-gen iPod nano ditched the tall and slender design for a widescreen and squat look. A lot of people didn't like the change. That and it had a smaller click wheel.

iPod touch (5th gen), 2012

The fifth-gen iPod touch was introduced to match the iPhone 5's new, longer 4-inch Retina display. It's not an ugly iPod, per se, but because it was so thin the camera protruded out (a design element we've seen used on the iPhone 6 and newer). There was also that questionable lanyard loop.

U2 and 90210 special editions

Look, the U2 special edition fifth-gen iPod classic was pretty slick ... from the front. The stainless backside, however had all the members' signatures engraved into it, and that is what ruined it.

The special Beverly Hills, 90210 third-gen iPod nano, however is probably the most tacky special edition iPod ever created. There are 2,000 of these ugly iPods out there in the world. Hopefully most of them have already been eradicated from this earth.