Hi Brian! You might get more answers if you move this thread to the Cafe section of the board, or if you post your questions in the NHL thread that's already there, but I'll give them a shot. I'm a Blues fan from St. Louis, so they might be a bit one-sided.
1. I suppose this depends a little on what area/time frame of rivalry you're looking at. If you're looking at the Central Division, I'd say yes. There are some other big ones that have developed throughout the NHL, like the Canucks and Bruins, Leafs and Senators, etc. But within our division it's certainly emerged as a new rivalry. It's mostly an on-ice rivalry though: the teams are very good and very evenly matched, and it's a close game any time they play. I think this is the main reason for a new rivalry. There's not a whole lot of off-ice hatred or sparring between the two teams-at least not yet.
2. Just a good hockey game. Both teams are very strong, and have excellent goaltending, so you get a close, tightly played game that's a lot of fun to watch.
3. That's a pretty tough question. It probably depends a lot on how healthy either team is on any given night. Right now, with the addition of Radulov in Nashville and a full roster in St. Louis...I'd say you'd see an awful lot of OT. But if St. Louis stuck to their game and played the way they do best, keeping it simple, they could probably win. But then I'm biased. In the regular season, Nashville had two regulation wins and two shootout wins, and St. Louis had one shootout win and then won the last game in regulation shutting the Predators out. It's close.