Green Eye is a good one - and in all shops make sure you ask to see their 'secret room' otherwise you only get to see the dodgy stuff in the main shop.
If you are looking for something specific then have a good look at the real thing to make sure that the fake one has all of the features, some of them are impossible to tell apart from the real ones!
They all have f.a.k.e stuff! you just have to walk down the corridors and you will be bombarded with offers for 'bling bling, copy watch, gucci, prada, luis vuitton handbag"
Good luck, it takes a lot of patience to survive this! ;)