The Grockle
Formally Croydon Seagull
Its all according what part of Croydon you are talking about though, its a pretty big place. Yes Thornton Heath and the like are horrible but places like Sanderstead and Addiscombe are as affluent as you like.
Addiscombe is a great place and has a thriving little town centre where you can still find a whole host of independant shops.