Fixed my problem, mostly.
RewriteEngine On
RewriteCond %{HTTP_HOST} !^www\..* [NC]
RewriteCond %{HTTP_HOST} !^dev\..* [NC]
RewriteCond %{HTTP_HOST} !^files\..* [NC]
RewriteCond %{HTTP_HOST} !^forums\..* [NC]
RewriteRule ^(.*) http://www.%{HTTP_HOST}/$1 [R=301,L]
I have to list all my subdomains manually, so I hope there's an easier way.
However, how would I modify this to redirect "www.subdomain.domain.com" to "subdomain.domain.com"?
If there is no subdomain, force www. If there is subdomain, take away www. That's what I'm trying to accomplish in the long run. Halfway there.