I can normally be found in any/all of several retro-themed groups (My home page is HERE:- Denis Evans / Retro Cavern), but lately I've been spending a lot of time in the excellent new (but already 1,000+ members!), Spectrum For Everyone group created by a friend of mine, Mark Payne (of Mark Fixes Stuff fame - great one-stop show for some cool tips and quirky / new hardware reviews!)... :)
In addition to this, I can also highly recommend the Commodore 64/128 group, and my friend Rob Fletcher's Console Computer and Collectible Crazy.
All of these are genuinely friendly, relaxed, retro-themed groups, with some great technical know-how and helpful advice to be found, in addition to a fun bit of banter and a great nostalgia trip! - Highly recommended for fans of either of these machines, and retro in general! :D