Well if you're on EU, i am absolutely no help to you at all. But if you're on US i can help you out. Most guilds on US spend their time on BleedingHollow. There are multiple guilds that accept multiple levels.
On Horde you have RankOnes, Warlords of Warsong, Nagaz With Attitudez
@Burg , Turtle Gang, and if you're experienced and are a good player, you could try getting into Gurubashi Surf Club, Skill Ratio, etc.
On Alliance there are less choices to choose from but still some good communities to join. There is District Nineteen, Bloodthirsty Geriatrics, or you could join my newly made guild.
These are the guilds on the US servers if you would like to find a good community to play with.
Oh and on horde tichondrius, there is Vipers. Can't forget about those guys!