Estancia and Penfold both make some good stuff.
Over the last few years, I've really gotten into Sake. We actually have a brewery in Berkely,
Takara, that makes some pretty good stuff. I really like their Nigori and it's great that you can get it at Safeway for $5 a bottle.
http://www.takarasake.com/
Also, there's a store in SF called True Sake that has some good brews that I've only seen there. The staff is very knowledgable and I believe they even have an online store now. Sake is an acquired taste, but I like it because not too many people drink it or know anything about it, and it kind of goes with my whole believing I was Japanese in a past life thing.
http://www.truesake.com/