Those who Never Were
Website: www.twn.5u.com
Global contacts @Xemulas, @Demonic Judgement, @Play (well, from june onwards, silly fool is having the time of his life in india)
Just a friendly group of players who've grown to get on really well, always welcoming people into our family 
Name: The Echelon
Website: The Echelon Website
Contacts: @Prov, @Mighty', @Flux', @Raz and @Mr Nice (there are fair few others who can be contacted, but these are the Leader Globals)
Notes:
Themed weekly Groups, TFs, plenty of teams, fantastic Coalitions, lots of Badge Hunting and PvP
Name: The Femme Fatales
Website: http://www.femme-fatales.org
Contacts: @Ace of Diamonds, @Caereen
Notes:
The supergroup for female heroes! The Femmes have been going strong since early 2005 and we are a friendly lot who encourage fun in the game through teaming and other SG events. We also have a Femme Villains group on Defiant (the Fallen Femmes) and a presence on Union.
Name:Generic Supergroup 101
Website: www.generic101.com
Contacts:@cunundrum, @rasmus or @Gully RX
Notes:We're recruiting. And a very democratic SG.
Defiant:
Cunundrum, Defender (Generic Supergroup 101)
Other servers too.
New Global: @cunundrumEU
Name: Shock Tactics
Web: www.shocktactics.org
contacts: @Riff
Notes: Huge base with all facilities (including a bar) we are looking to re-energise the SG after a quiet winter period so if you have something to offer give us a shout!
Thelonious Monk
Name: 47 Ties
Web: www.47ties.tk
Contact: @AG
Notes: We have a lot of SGs, anything with 'Ties' in it is usually a Ties SG. Our bases have pretty much everything 
would it be worth making this a sticky? Am thinking it'd be nice for any new players to simply browse the server's forums and see a definitive list of SGs.
If that's a bad idea, feel free to punch me in the ovaries, shouting "Bad Sam!"
Name:
The Order of Cruciform Swords
Website:
http://www.ootcs.com/news.php
Contacts:
@Omega MCX, @Cambo, @Sinergyx
Notes:
One of the older supergroups out there the swords are now recruiting fresh blood after a somewhat quiet January. We're a friendly lot with a lot of coalitions who like to play on and off at all hours of the day so theres usually someone to team with, as well as teaming where into our tf's pvp and a little bit of badge hunting too. 
Captian_Solaris did an excellent template here . And, yes, making it sticky would be a good idea.
Here's my addition:
Name: Wizards Inc
Web: Wizards Inc
Contacts: @LeighB
Notes: A small Super Group thats been around for a couple of years. Originally started for a group of friends, but now open to any who want to join. Most players are casual, and I dont think anyone will mind saying, of the older generations. You should find us friendly and helpful, with a useful base and some experienced players. We play to have fun rather than as power gamers and were always happy to offer advice.
Name: InnerCircle
Website: TBA
Contacts: @Ris, @Mr ?, @Solid State, @Seigi
Notes: Active since CoH EU Beta, recruiting for players of all ages and ability. SG Teaming/TFing popular amongst members. Mid-level base - currently hoarding prestige for no apparent reason
I thought it may be of interest/use to folks to start a list of as many Defiant Supergroups as possible. To advertise said SGs, etc. Please keep your posts to the relevant information about the SGs. I have posted below details of SG I'm in, please keep to a similar format
Name: The Awfully Nice Chaps
Website: http://www.freeyabb.com/phpbb/index.php?mforum=tanc
Contacts: @Death Badger, @Dameron, @Target, @Wilfred
Notes:
Run a SG only night on Mondays (Villains) and Thursdays (Heroes) on either Defiant or Union, which involves levelling the same team from 1 to 50.
Fairly mature and like a nice cuppa.