I don't know who recommends random_page_cost=1, but IMNSHO it's a bit silly. Even SSDs handle sequential I/O better than random I/O. Values between 1.5 and 2.0 are more appropriate. I wouldn't really recommend 1.0 except when you know the data fits into RAM. There are other options that affect costs of random I/O, e.g. effective_cache_size.
