I've just checked a shop nearby (this shop is not famous by its cheap prices) and prices have little sense (min - max):
6200A 256 MB AGP (117€ - 148€)
6600 256MB AGP 179€
6600GT 128MB AGP (215€ - 249€)
6600GT 256MB AGP 299€
Is 6600GT much better than 6600, and this much better than 6200?