I'm a regular on the following boards:
A Sailor Moon Romance
Henshin Justice Unlimited
Romhacking.net
I used to be a regular on Rangerboard until some baka of a Mod there banned me for life as he accused me of trying to open a second account on the site [he's always had it in for me just because I dared stand up for myself and complain about not having a controversial thread there locked...]
Meanwhile, I run my own messageboard which is dedicated to Asian Pop Culture called
AsiaNami and which covers everything from Anime and Manga to Tokusatsu and Sentai to KPop and CantoPop and more! I've found it to be an enjoyable experience running my own board and unlike some messageboards where the Admins and Mods seem to be either on a power trip or come up with some crazy rules which just spoil the fun for everyone, at the end of the day, I just want the members of my board to have fun and have enjoyable and fun discussions on anything to do with Asian Pop Culture without too many rules [But in case anyone's wondering, I would give out instant life bans for things like racism and other quite serious things if they ever appeared on the board]