Amy Winehouse found dead (age 27)

But shes not a legend.... and probably never will be.

Gary Thain, Bryan Ottoson, Sean Patrick McCabe, Rudy Lewis, Alan Wilson aren't legends. But are commonly mentioned, alongside other singers and artists, who died because of drugs, suicide or any tragic death at 27 years old. There are other members that aren't even known for most people, but regardless can be included in the "27 club".

That club, is made of Robert Johnson, Brian Jones, Janis Joplin, Kurt Cobain, Jimi Hendrix, Jim Morrison, Amy Winehouse alongside many other artists, these are the most famous ones mentioned as members of the club.
The reason they are in there is the fact they're artists, that had a death because of one of the reasons mentioned above, at 27 years old. The question if they're considered legends or not, talented or not, good or bad, is too subjective to be the reason they are in there.

Robert, Kurt, Brian, Janis, Jimi, Jim and Amy are the most remarkable members or the club, the ones that are remembered more oftenly, not the only members.