I would really check out the list of forums at the SEO Round Table (http://www.seroundtable.com/forums.html) It gives a listing of all of the most popular and biggest SEO forums on the Internet, even with ratings and descriptions of each.
To be honest though, all of the big SEO people all are members of all of them and post to all of the biggies. The SEO community is small enough and tight-knit enough that everyone knows everyone else by name, and odds are you'll recognize more names than not if you frequent a couple of the bigger SEO forums.
I have been in the SEO business for over 5 years and yes I am a member at them all ;)
I have also started http://www.sitetutor.net back in the days.
I can tell you from a quality standpoint that digitalpoint and sitepoint alike are the only places to go to get good and frequent information.
The other ones are over moderated and not moderated by experts (you can imagine what that does to the quality).
About seo chat, they have random people write articles and get paid for them. Many of those articles have been proven wrong.