Overclockers UK are hard to beat:-
http://forums.overclockers.co.uk/
The forums are ran with an "iron fist" though, the mods and admins have very strict rules there.
However, the place is a veritable "goldmine" of info on pretty much any subjects you care to mention. From Cars, bikes to motherboards and PC's.
I post there regularly and have found it a superb place to both network with others and get info and advice from.
Their "Members Market" on their forums is where I pretty much purchase all my PC stuff from. There are some amazing bargains to be had there.
A great community all round, as long as you watch what you post and dont upset the admin and mods there by even a little amount as I said, they tend to be a wee bit "touchy" and will ban anyone at the drop of a hat.