Best I've seen were

<R.Kelly PvP'd on Me>
<Steve Irwin Needs A Rez IRL>
<My Main is in the Shop>
<South of Heaven> and <Absence of Faith> are both good for horde I think...<RED> was a good one too...so many good ones out there it's hard to judge  =)

The worst one was <Kittens Mew Mew>. Phail.

A few of the best I have seen (all on Silvermoon server) that still make me laugh when I think of them - The Legion of Mediocrity (certainly expect high standards from that guild); I Forgot How to Play My Class; Knights of the Winnebago. Also, I have seen WOW Chicks Have Stamina around alot, which I have checked into and members are all women players. I think that's a cool concept and cool name.

<Kogurasumaru>

Well....me and some friends decided to take a name that has som'thing special especially that we don't play much WoW.But still....we wanted to have mysterious and tough name. We had some names in our minds like:
1<Belfgay?>
2<We rock this server>
3< and 2 imaginary chicks>
4< My best friend and WoW>
5<Farty year Old perv>
6<LOLCATS>  => my friends love those kitty's xD
7<The Forgotten Legion> => This name is used on some servers but it looked cool. Its like the come back of the Horde ;p
and the last name.....
  your name <and the Nubz> => this is a guild full twinks on the server zuljin i thought.

But guess which one we chose...... 

SUPERADVENTURE CLUB!!!!!!! from SOUTH PARK :D

the best I ever seen was <Kentucky fried gnomes> and <me and my gnomies>


the worst was < the horde embassy> => doesn't make sense

been in a guild called .... <For Our Souls> made me giggle so i joined :P

The worst name I have ever seen is enemies of the world...like that is so hardcore..lol

<relax chump> good one im in it <faith> is a good one has a thing over the a cant make it now that was on my old server <anomaly> <tier> <fist of entropy> top raiding guilds on my server all great

I think the worst is <FOR THE HORD> from Nazgrel. I mean, fail.

I thought of a funny guild name: <I broke the Nerf stick>

Just Saw <BRB FBI ERASING HARD DRIVE>

worst name?  someone was paying for sig's for a guild called <MAYOR OF IRONFORGE> Bad by itself, even worse since he spelled mayor "mayer". 

The Funniest and Best Guild names:
*<Laser death tree house> (alliance)
*<Legion Of the Sitting Ducks> (lol!) (horde)
*<Ooh a Piece of Candy> (haha)(horde)
* <Team Cupcake> (raid guild) (alliance)
* <Doom and Rainbows> (raid guild)(alliance)
* <Grand Theft Mana> (alliance)
* <Shadow Squirrels>(horde)
* <Casket Crew>(horde)
* <Made in Mexico> (have to be Hispanic or Mexican to join)(horde)
* <SapNnapN> (rogues guild i think that went under)(cant remember)
* <Les Efantes De Alliance> <----mY guild very cool guild =P(alliance)
* <Pwning Pinapples>(alliance)
* <We Deliver Pwncakes> (alliance)
* <The Exalted> (good guild and friendly too!)(alliance)
* <SuperMegaIcecreamParty> (lol)(cant remember)

WORST: <Is probaly drunk> (alliance)
      <Pointy end of the Stick> (horde, but its a banking guild =P)
      <We hate texas> (?) (alliance)
      <Whip cream Bikini club> (stupid) (aliance) (went under i think)
      <I Blame Pod> (?) (alliance)


  {All the Guilds are on Terenas Server (Well most of them r.)