The most recent thing that has happened to me was with Bioware's Neverwinter Nights. I originally bought NWN when it first came out. Played it through and loved the game. I bought every Bioware expansion that came out. Recently, I wanted to reinstall the game but I couldn't find the CD Key for my last expansion. I have the media. I paid for it. It is completely useless now. So I searched the forums for ways to get around this, get a new key, etc. Turns out there is no way to get a new key and I wasn't about to download one of the keygen programs that load your system up with trojans and zombies. So I have spent about $100-150 USD on the games and accessories and they are completely useless and neither Atari nor Bioware will issue new keys. So I went out and bought the NWN "Diamond" edition with everything on it. This really sucks because I had to spend another $50 to get a CD Key to use the software that I already bought. I personally think CD Keys are designed to make paying, honest customers buy the same software over and over again, just like my case. I rather not spend the time and energy to pirate the game I already own because it is safer and easier to re-buy the exact same software. In fact, I am convinced that they bank on this behavior. This is why I hate CD Keys.
BTW, there are a ton of NWN cracks, keygens, iso images, etc out there. Once again, CD Keys have done little to nothing to stop, or even slow, piracy. Instead, it just pissed off a paying customer.