Best is relative, but if I were compiling a list of the best North Country spiders, the Winter Brown would be near the top. While legacy fishers of this fly may have intended it to represent a stone fly, the Winter Brown is for my purposes a caddis imitation (and the trout have agreed on occasions too numerous to mention). Much to like here, including a not-so-common hackle feather and the delectable secret sauce that is peacock herl.
The Winter Brown
Tying notes: The head is tied in first (I tied this fly “wrong” for years). Two or three close wraps are all you need. Next, attach the hackle, then wind it rearward, secure, and clip. Stroke the hackle fibers toward the head (this makes it easier for you to construct the body), then wind the body with two layers of silk. Tie off just behind the hackle, and stroke the fibers back to their natural position. You can find a general North Country spider video tutorial here.