Well, that's the shout I've seen in trade, general and even LFG channels lately, and it has made me thinking over the whole situation of guilds as whole.
My response to that call has been to ask in return for the caller to define good guild. I've only gotten one response stating "to form an arena team"... Hardly what I would a good guild to be.
Most certainly a good guild is depending on the phase the player is going through in the game. Like I've been commented in my earlier posts, currently it seems that WoW guild system cannot deliver anything more than a well maintained friends list in terms of grouping and instancing. Well, perhaps the guild chat.
Lets see the phases of a WoW player.
1. Entry to the game
Newbie, noob, newcomer. All is great and fine and lovely and it's all ooh's and aah's until the grind gets you. In the first 10-15 levels you really don't need a guild to guide or help you, and the first instances are a blast with a PUG (like a PUG could ever be a blast while levelling...). At one point or another you will encounter a quest or challenge you need help with and a helpfull levelling guild is what you look for: a group of people to help you get more levels, help you with your questions and -most importantly- to belong to.
2. Levelling stage
From certain point on (your mileage could vary) you will be levelling on rails. Levels pass you by, you overlevel instances faster than you'd like to, and you find yourself looking for boost runs, specific gear and hidden profession trainers. Levelling guild you joined is still the one if it's doing it's job, and you're relying both on their help and your own knowledge of your capabilities. For some -like me- this is the best part of the game: stories, quest lines and challenges.
At this point the Guild Bank will become your friend, if you so choose, as you will be needing materials for your quests and profession training, but also being short of money the now and then support of the Guild Bank repairs.
3. End Game
At the end, you will be seeking for the opportunity to raid. If your levelling guild has that function, the better. If not, you'll be seeking for the guild who would recruit the power leveller like you. The guild selection becomes a crucial question at this stage, as you will be requested to work with the guild, not the other way around.
The other activity I mentioned earlier would be PvP: forming arena teams. Knowing nothing about it, I let it be.
Thus the call for Good Guild is a vague one. What are you really looking for: power levelling guild, relaxed casual one, fun guild, achievement whores?
Define what you are looking for and you MIGHT find it.