Primarily a mail-order house, you can go there and fondle the yarns in person, including in their closeout/discontinued room. It's a nice drive, and there are plenty of wineries and tasting rooms nearby if you need a different excuse to get out there. And, since their entire stock is online, you can check out the catalog before you make the drive (if looking at a PDF catalog doesn't drive you bats, that is).

They stock Manos del Uruguay wool, Lamb's Pride in worsted and bulky, and a raft of sock yarns (including Wildfoote). And they probably have the best needle collection in several counties, with Brittany, Bryspun, addi Turbos, Inox, Clover, Crystal Palace, and addi Natura.