What are the other “best” forums/message boards for non-catholics? I know there is Christianforums.com but are there any others that are fairly large, welcoming, and have places for each denomination?
Not all of these are good boards:
Christianforums was far too big for me, although I did like the fact that it had a place for different denominations. The BBC have a religion and ethics message forum with boards for Christians, Muslims and Jewish faiths, as well as an ethics forum, though be warned - the discussions do get pretty heated since there are a good number of pretty combative atheists too. (Its a topic board rather than a faith community online).
If you google ‘christian forums’ or ‘christian discussion forums’ you will find quite a few, though I would urge you to be careful and use discernment. Most should have a statement of faith - check those out first and then ‘lurk’ for a while, just read the postings to help you get a feel for the place.