I was searching for a good PhotoShop discussion forums, and I got the idea to start this thread.
So list your (other besides HA ) favorite/useful forums here (no warez/piracy forums), and give a little explanation.

Here are some for starters:
Audio/video:
http://forum.doom9.org/ - Most famous video coding forum. (Who doesn't know this...?)
http://virtualdub.everwicked.com/ - Unofficial VirtualDub support forum
http://www.avsforum.com/ - Probably the biggest Audio/Video-Hardware forum.
http://www.diyaudio.com/ - General audio/hi-fi forum.
http://www.head-fi.org/ - Headphones, cables, hi-fi, audiophiles.
http://www.3dss-forums.com/cgi-bin/wwwthre...threads.pl?Cat= - 3D Sound Surge forum. Covers mostly computer audio hardware.
http://club.cdfreaks.com/ - CDFreaks forum. Burning, ripping etc.
http://groups.google.com/groups?hl=en&lr=&....apps.photoshop - Photoshop usenet newsgroup.
http://groups.google.com/groups?hl=en&lr=&...phics.photoshop - Another Photoshop newsgroup.
http://groups.google.com/groups?hl=en&lr=&...otoshop.windows - Yet another Photoshop newsgroup.. (I was searching for PS related forums, that's why these PS-related links. )

General computer usage related forums:
http://www.tutorialforums.com/ - Nice forum covering several areas of interest, like Graphics Software (PhotoShop, Flash etc.), Programming (PHP, Javascript etc.), Web-related issues.
http://arstechnica.infopop.net/OpenTopic/page/a/cfrm - Ars Technica is very big and quite chaotic place (too chaotic for me). Covers computer hardware,video/audio,operating systems and software etc.

Ok, there were some.. Now list your favorite forums or just forums you think should be listed..

http://www.dslreports.com/forums/all - check it out y'all, useful.

http://www.computing.net/

It has support forums for Windows, Linux, and other OS's with a huge archive of previous posts to quickly find answers without having to post anything. Just about everything I've needed to fix in Win98 has been gathered from the Computing.net search function. There's alot of newbie questions (annoying) but the search function is pretty reliable.

http://headwize2.powerpill.org/ubb/forums.php - Another headphone forum (with DIY-knowledge base)

http://www.mp3pro.com

The name already says it all, I guess.

http://www.audiocoding.com/phorum/list.php...?f=1&collapse=1

Menno's website with a forum about AAC and MP4, also with a very useful Wiki (user-editable knowledge base).

http://www.everwicked.com/forums/forumdisp...p?s=&forumid=36

This website mostly deals with Video issues, but has a nice forum, too, even with an own AAC board. It is also home of the MPEG4IP Guide, a good resource for people who want to stream MPEG-4 content (video and audio) in the internet for free.

http://www.supergamez.hu/listazas.php3?id=1011830455

The Mpxplay forum, still my favorite audio player.

http://www.jetaudio.com/jetcast_directory/...anguage=english

The JetAudio User Forum (there's also one for developers and another in Korean ), might become my favorite audio player, if it was smaller, would have native AAC and mp3PRO support both for encoding and decoding, came for free and so on...

http://www.chip.de/community_events/chip-f...ardList-page=1&

German Vorbis zealots bashing innocent newbies who dare to ask something not related to the one and only compression format - always good for a laugh...

Elite Fitness Discussion Boards - Bodybuilding, Anabolics, Diet, Life Extension, Wellness, Supplements, and Training.

http://boards.elitefitness.com/forum/index.php

ff123

Huh?!

Yeah, the Chip forum is full of gits (as every large public web board is), but at least, thanks to the perseverance and hard work of three fellow forum members of yours , the amount of misinformation being spread in the MP3 forum has *greatly* reduced. You should rather look at Heise's or PC-Welt's forums if you want a good laugh.

</OT>

I was there only once, but when I had some hardware/Windows questions, the guys at AnandTech forums were pretty helpful. Can't say anything about the general quality of the board though.

AVSForum was suggested above. I follow this board there daily:

http://www.avsforum.com/avs-vb/forumdispla...p?s=&forumid=26

It's the Home Theater PC board and it runs fast and deep on using a PC to drive a big screen. Usually for DVD, and usually using projectors, but it is a great place to watch all media coming together and PC's and Consumer Electronics merging.

http://forums.animeondvd.com/dcboard.php

Anime on DVD, with discussions on R2 imports, reports about progressive scan, dub/subtitles, anamorphic transfers, edge enhancement...

HomeTheaterForum
for home audio, home theater, dvd, etc.

http://www.musicex.com/cgi-bin/yabb/YaBB.cgi MediaJukebox and MediaCenter Forum
A good place for a very good Multimedia Jukebox, there you can post problems (bugs, questions) about MediaJukebox and/or Media Center and other things with the company of a excellent community of users and developers ***** ( 5 stars )

http://www.hardforum.com

Mainly computer and overclocking related, lots of fairly knowledgable people with those areas. Some other stuff on cars, web design, art, and like everything else under the sun.

http://www.genmay.net

Place when your really bored and have nothing else to do, like a big chat room that is a little easier to understand.

http://css-discuss.incutio.com/

Technically a mailing list, lots of very very very very very intelligent people when it comes to Cascading Style Sheet.

Someone already posted Arstechnica, thats another pretty good forum for computer related stuff.

www.ntfs.org

formerly xp-erience.org

A great place for WinXP tips tweaks and discussion

now covers more than just XP

I just discovered a new forum on Digital Radio Mondiale (DRM) with several boards covering all aspects of this new technology (using analog AM frequencies for digital, aacPlus-encoded radio broadcasts in mono):

http://www.drmrx.org/forum/