Although they are become seldomly used now, they will probably never become obsolete, unless if companies start releasing software on Flash drives. Think of it this way, although many forms of software are being downloaded to be installed, with things like OS releases like Leopard, they almost need to have an optical drive, that thing took like an hour to install over DVD, and simply imagine how long it would have taken to install over the internet (days and days). I cannot really see them eliminating them from the computers soon, but it will be interesting to see how they deal with the next big OS release and the MBA, I almost wonder if they will switch to flash drives that have the OS on them (a mighty big flash drive then), and if you include the price of the flash drive with the actual software, then you are doubling if not tripling the cost to buy it. But I can definitely them removing it from computers in the next 5-10 years, but they will probably keep an option to have an external one. Just my two cents.
Why do people join just to post crap like this, it is annoying and doesn't contribute to the thread whatsoever, please, grow up now and if all you have to do in your free time is to join forums and annoy members and distract threads there, then I suggest finding a new hobby.