I'm not sold on BD no, as my vision is unable to tell the difference between something that's HD and regular D, so buying into a more expensive technology would be a waste of money which I can't justify. Especially given how many DVDs I already have and the rate I collect them. I do have an HDTV though due to the forced cable upgrade a while ago, however.
There was never a forced upgrade. The cable company may have forced you to upgrade to a digital box, but your old TV would have worked just fine.
It's not just video that gets an upgrade though. The audio of most blu-ray discs is quite superior to dvd. A lot of films are granted a lossless audio track on BD.
The audio upgrade is an even smaller upgrade though. Dolby Digital/DTS has been trying to convince people for years that the only audio loss was information we can't hear anyway. They can't turn around now and claim we can hear the difference.
Now, don't get me wrong, I use lossless audio whenever it's available, and I probably have a better speaker system than most Blu Ray owners, but I wouldn't buy Blu Rays just because of the audio. And if you only listen to Blu Rays through your TV speakers, then you won't hear the difference at all.