GenBank release 175.0 is now available here via FTP from the National Center for Biotechnology Information. It contains data as of Dec. 15, 2009. The new release comprises approximately 110 gigabases and 113 million entries from non-WGS, non-CON sequences, and 158 gigabases and 54 million entries from WGS sequences.
Uncompressed, the 175.0 release flat files require about 422 GB for sequence files only. The ASN.1 data require approximately 381 GB.