Turley - consistantly one of the best, complex flavors, a long wait to get on their mailing list.
Rafanelli - excellent Dry Creek Valley Sonoma producer year after year
Outpost - high end limited production - need to get on mailing list
Dowling Family - another good one - mailing list
Rosenblum - many different vinyard designations - overall one of the best and most consistent, big production and accessible - high fruit and alcohol - try Hendry, Kratka, Annette's, Allegria or Rockpile vinyards
Ridge - Lytton Springs (another Dry Creek Valley) in my favorites year after year - they have some other good ones, too, which vary
Ravenswood - haven't been too impressed with theirs in the past few years although their Vintners Blend is a good everyday zin when it's on sale
Seghesio - another good Dry Creek Valley vinter - usually pretty good
Some others which I find to be hit and miss are Cline, Dry Creek, Lolonis, Murphy-Goode and Martinelli (their Jackass Vinyard is usually a good one).
I like to pick up say, 3 bottles the guy at the wine store recommends and conduct my own little tasting. You can freeze the opened bottles you don't finish.
Have fun looking and let us know if you find something worthwhile.