In Seattle, I was cheap and took the lowest form of cable TV offered: basic cable, which was just under $13 a month. For that I got the broadcast stations, Discovery Channel, and a few other channels like CBC and Weather.
That option doesn't exist here, and after wrapping my head around spending an extra $30 a month for cable, but one that includes the typical extra channels, I decided to go crazy and spend an extra $10 on top of that to get a "digital cable with high definition" subscription.
What the heck, I definitely wanted to get the Sci-Fi Channel, Learning Channel, History, Comedy Channel, Outdoor Life, and a few others. Now I can watch Battlestar Galactica, The Daily Show, triathlon coverage, and so forth. From there it was a small leap to HD, after all I had planned to build my own OTA HD receiver using the HD-3000 card. And, my TV is 1920i ready. I can still build my own HD receiver, but it is far easier just to sign up and use the HD receiver the cable company provides. Besides, I can only get the Discovery HD channel through cable.
I like doing my hobby video stuff this way: have some off-the-shelf component that works (ReplayTV, HD cable receiver) and then go off and fiddle around with extra computers, without the pressure and anxiety of making all that stuff work. ;)
I've been trying it out for the past few days, and I'll have to say HD looks really darn good. Part of this is the fact standard definition doesn't look as good on a large screen TV.
The HD package I get includes the HD version of the major channels plus Discovery HD, which runs programming that specifically shows off HD: a show about hot air ballooning in Vermont (which was largely just panoramic views); a show about animal predators; a show that was simply stunning Grand Canyon landscapes; a show that visited national parks along railroad lines. There isn't much HD content yet, although most stations have a few hours during the weekdays.
As far as shows go, a higher resolution does not make the show better - a crappy show in HD is still a crappy show. But for the shows I like, I will definitely watch the HD versions, since they look much better. The only drawback is I don't have a way to timeshift HD shows. Yet...
Anyway, I'll try not to become an HD snob and complain about watching shows in "standard" NTSC resolution. ;)