Here's one for Emperor's Children:

http://forum.emperorschildren.net/

Here's a rather helpfull site for all you nid players out there,
http://thetyranidhive.proboards28.com/,
-Malant

40k Terra
I've only been a member there for a few days, but they are very welcoming. There are a lot of knowledgeable members, although it is much closer to "LOL WTF those aint roxxorz" than ATT, but then again who isn't? It does have large signatures, but as I found out earlier today you can choose to not view them.

A pretty good general 40k site. If you join, look me up (I have a strangely similar name...).

that's exactly it, I often find myself doing that too. i wonder if they ever poll their members and ask them if they view them or not or can view the stats on how many use that control? Can't stand it when sigs are longer than posts!

Thanks for the links SpartanTau

My fav Blood Angels forum

http://www.exlibrismortis.org/

But of course, BA was my first army - picked right about the time the (first) Tau were released, but I was commited already to the red.....
So, started Tau the year later.

I'm surprised that http://www.bolterandchainsword.com hasn't made an appearance yet. It's a forum for anything in power armour.

www.bolterandchainsword.com has been on there for a while, but it's the first i've heard of www.bolterandchaonsword.com.

Good site?

Yeah Yeah. Typing a bit too quickly in the rush this morning.

Sheesh.

There's Underempire for Skaven [WFB]:
http://underempire.net/?act=idx

and http://www.librarium-online.com in the general links for all games

Good ol' painting site:
http://www.chestofcolors.com/cofc-postnuke/

General 40k-
http://www.ageofstrife.com
http://www.belloflostsouls.blogspot.com

Those are some of them that I visit. The other ones have already been listed.

A good Vampire Counts one. http://www.vampirecounts.net

Are you sure that's for Vampire Counts? With a URL Like that, it could be for anything!

http://www.Gaiaonline.com isn't a pure Warhammer site (more for manga/anime fans), but they have a guilds section, where you need to apply to join groups. There are one or two WH guilds in there, but to be honest, not much happens in them... Last time I checked, the last post in the Tau thread was 2 months ago. I think I'll stick with ATT, thank you very much.

And the best one for all power armour armies there is.

the forum'a adress is now actually http://exlibrismortis40kboards.yuku.com/directory

http://battleglade.freeforums.org/portal.php and http://asrai.org/ for Wood Elves.

Actually, http://www.ironhands.com/necro.htm Is a conversion site for quite a few armies, and not a forum at all. I just thought it had some excellent conversions and tips.

One that has not been mentioned but very good...High elf specific but you will find it is a great forum itself-- http://www.ulthuan.net/forum/portal.php

There's Shas'O'Cam's http://s10.invisionfree.com/gravtankonline for 40k in general, however it focuses on Eldar, Dark Eldar and Tau- the grav tank users. Sorry for posting this shas'o'cam, just had to tell everyone- it's quite a good site.
Has anyone got a good Chaos one?

Try this one for Tyranids:

http://thetyranidhive.proboards28.com/index.cgi