What's the best Apple product ever designed?

Macintosh 512K aka 'fat' Mac. Increased memory made it suitable for business use. Built-in Localtalk file sharing, plus the Laserwriter came out around the same time.

Apple pencil!

I think it depends on how old you are...for those of us who remember a time before personal computers, that first desktop was mind blowing, but the social game changer was going from a huge tower or 50 pound book of CDs to carrying all of your favorite music in your pocket at just 5-6 ounces...for the iGeneration, airpods.

I adore my Ipad because you can work, play, read, watch videos, whatever you want

I still use my iPod.

iMessage

I haven't heard anyone mention the PowerBook G4 yet but that product casts a long shadow. I remember the impact when they released it, there hadn't been a laptop like that on the market. And they haven't really deviated from that esthetic for their laptops since then.

Newton MessagePad

By far the iPod classic. I also really liked the iPod nano touch which I wore around like a smart watch before one existed. It was actually amazing.

iBook G3. Iconic.