HDTV will be a huge boost for hockey. You can see everything absolutely perfectly. My family is getting a 70something inch projection TV almost entirely for hockey games.
Once HDTV starts to catch on faster, hockey will be a much more TV-friendly sport.
The World Series of Poker, Professional Bowling, ect have good rating because they have that "curious" factor. I watch Professional Bowling not because I like bowling, I hate to bowl, but because it is interesting and rare.
Hockey, being more mainstream, doesn't have that to help it out, but at the same time doesn't have the fan base to compete with Football, Basketball, or Baseball.