it's tough to say really.
i still use my 30GB 5th gen classic in my car. it never leaves my car and it works great. they will always hold a special place in my heart.
that being said, the simple fact is the product is getting elbowed out of the market. there is really not much left to improve upon the device itself... and no longer are people buying new devices to carry around separately. the ipod touch line has a few years more of a shelf life because not everyone has embraced (or can afford to embrace) smartphones.
but why would anyone really want to carry around a separate music player when there are perfectly capable ones lumped in to their cell phones (along with broadband internet access, games that rival the newer portable game consoles (also, imo, a dying breed), 8 megapixel cameras, and so on and so forth.
if the ipod is discontinued, it would only be surprising in the sense that it really is the device that "saved" apple. people can say the Mac did, but everyone knows that windows/pc were crushing the mac through the early/mid 2000s when the ipod brand took off. it was then, and its seamless integration with itunes (bloatware, not very good, but people ate it up anyway) that their laptop market began to take off... first with the college-aged crowd, and later with others. the iPhone and then iPad came later.
in my opinion, the iPod classic line has run its course. there may be another generation or two of the touch models, but that too will soon give way to smartphones exclusively.