I really like the USA Today salary site as well -- it goes beyond the NHLPA site as it keeps track of historical data.
A couple that I really like:
1.
http://www.nhlcbanews.com/ - Includes the most up-to-date CBA...
2.
http://www.hockeyresearch.com/ - Personal site of a freelance hockey researcher - It's become dated, but some interesting stuff and links.
3.
http://www.whowins.com/home.html - Who wins? Offers historical victory percentages for best-of-seven playoff series.