Just popped out to my local PC hardware store here in suburban Tokyo. They had at least two models of serial ATA drive.
The Maxtor 7200 rpm with 8 MB cache (160 MB) is 20,200 yen ($168) and the 7200 rpm 8 MB cache (120 MB) is 15,500 yen ($130). These were boxed--I am sure if I went to Akihabara and looked for bulk drives, they would be about 25% cheaper.
On the whole, I think Asian-built PC hardware is much cheaper here than in the US but I just wish the Gigadesigns G4 1.4 GHz accelerators weren't 25% more expensive here than in the US because I want to give my old 733 MHz G4 some new life for 6 months until the 3 GHz G5s appear!
Decisions, decisions.