What
Carnaby Street was in the 1960s, so is Camden Town in the 1990s & 2000s, only on a far larger scale.
If you're in London and looking for mainstream clothing, footwear or invaluable lifestyle accessories then stick to the traditional shopping areas; if you want something alternative then get down to Camden Town on a sunday.
Whatever your personal definition of alternative you are guaranteed to find it on one of the countless stalls which criss-cross the maze of passageways and buildings that make up the markets of this part of London: ravers, hippies, goths, mods, bikers, freaks, wierdos and just about the entire transient population of Europe under the age of 30 will be here. Camden Town is rapidly becoming a lot more commercial and touristy than it used to be, but it's still the best place to go to get stuff that just doesn't seem to exist anywhere else in the world.