To your first question, I'm going with dubs. Why would I want to listen to someone speak Japanese, try to keep up with reading a bunch of English writing, & miss half the actual action on the show? Simply dub them in English, let me watch the show in peace, & if the lips don't match the words, it will just remind me of my old Godzilla movies that I enjoy so much.
To your second question, I believe this is a pointless debate, especially if referring to DVDs. After all, there's no reason DVDs of animes can't all include both dubbed & subbed versions of the show. That way, if you like subtitles, you can watch the show as you see fit, & then if you invite a friend over who is like me, you can play the dubbed version for them. Best of both worlds!
As for animes shown on TV, you risk having a smaller audience if you play subtitled shows instead of English dubs. After all, fans who like subtitles will still often begrudgingly watch a dubbed show & gripe about it later. However, fans who hate subtitles are liable to do as I often do: turn on the show, realize it's subtitled, & not even give it a chance because of all the reading. This is exactly why I won't watch foreign films like French movies. If I wanted to watch movies in French, I'd learn French. Likewise, if I wanted to watch animes in the original Japanese, I'd learn Japanese. Most likely, I wouldn't be a fan of the animes I do enjoy if they had never been translated to English.