I bought my 160 GB iPod Classic six years ago, and yes, I'm quite pleased it's still going strong, despite being dropped who-knows-how-many times and spending most of its life in my cars (often in somewhat extreme temperatures for a consumer electronics device).
I much prefer it to an iPod Touch or iPhone for playing music because of the much larger capacity, the simple interface, great battery life (even after all this time), and the physical buttons that are easy to use while driving (I can skip, pause, or replay a song without taking my eyes off the road). I much prefer it to offerings from other manufacturers because it has a cleaner interface, syncs automatically with iTunes (all I have to do is plug it in every few weeks when it needs a charge), and use databases and metadata in an intelligent way. All the other players I've seen have busy, garish interfaces, have controls that may approach but can't match the elegance of the click wheel, and use the file system for both adding music from the computer and playing it from the device, which is far from ideal, even with a well organized collection.
Really, the only substantial ways Apple could have improved it would be to switch to flash memory (say 256 GB, for even better battery life, reliability, thinness, and probably most importantly, parts availability) and switch out the old dock connector for Lightning. It's remarkable that the iPod has fallen so far from prominence since the iPhone that it isn't worth updating it at all anymore.
Unfortunately, my iPod won't last forever; the hard drive or the battery will eventually give out. I'll do my best to find parts and keep it going, but it would be nice if there were something on the market I would consider for a replacement. From my perspective, there isn't; everything else falls short.