I honestly can't say I had a favorite forum that I was a part of as it was more like I had favorite people I like being around and people who liked being around me so basically where I went they followed and where they went I followed. As long as they were there, not much else really mattered as I will just deal with it as it comes.
Without a doubt, Dashing. I ran it for 11 years, made many memories and lots of friends over that time.
Would I ever want run it again? Probably not. It was a large time commitment and dealing with spambots on a daily basis was jading. Would I run a forum again? Eeeeehhhh, maybe, though I'd probably opt to run a Discord server instead these days.