I skipped Napa and Sonoma because they seemed too obvious. These are mostly northern towns, since that's my zone, but I am open to your additions!
  1. Santa Rosa
    I really didn't appreciate it until I left. The metropolis of Sonoma County. Required: Copperfields Books & Music, Monti's for martinis and oysters, Russian River Brewing Co for Pliny the Elder and pizza. If you loved the movie "Peggy Sue Got Married," check out my alma mater, Santa Rosa High School, where it was filmed. It's also just an aesthetically beautiful building.
  2. Guerneville
    Situated in the Alexander Valley, north of Sonoma County, Guerneville was historically vacation town geared toward San Francisco's gay community. It still has a big gay scene, as well as plentiful great wine and food. Rent innertubes and float down the river with a cold beer, eat at Boon, drink wine at one of the many nearby vineyards, and stroll around Main Street and, most importantly, gaze at 1000+ year old trees at Armstrong Woods.
  3. St. Helena
    This is Napa's lesser-known, chill little sister (the @keonovak of the wine country, if you will). Fabulous restaurants (don't miss Farmstead @ Longmeadow Ranch, and Archetype), and good wine. I love Beringer Vineyards.
  4. Calistoga
    While you're in St. Helena, swing over to Calistoga. Lots of good food and wine, but my favorite thing to do there is spend the day floating at Indian Springs Resort & Spa. Natural hot pools! Like swimming in warm Pellegrino.
  5. San Louis Obispo
    Sleepy little town, a stone's throw from Hearst Castle. Stay at the weird but awesome Madonna Inn.
  6. Arcata
    Crunchy little town in Humboldt County. Great food and very good coffee.
  7. Bodega Bay
    Beautiful beaches, great antiques, and Hitchcock's "The Birds" was filmed right on the main drag.
  8. Santa Barbara
    Santa Barbara is just an hour north of LA but it might as well be in a different world. Slow-paced living, gorgeous beaches, and a quaint small town vibe. Eat dinner at The Lark.
  9. Santa Cruz
    So much more than a college town. Stay at the Hotel Paradox. Good food and lots of good local beer.
  10. Half Moon Bay
    Perhaps the best thing about Half Moon Bay is the Creekside Smokehouse. They make the best lox I've tasted outside of New York. I also love Pasta Moon, and the beautiful beachy vibe of this little town.
  11. Ojai
    I'm biased bc I'm getting married there, but it's a cozy town with a small main drag and a gorgeous hotel (Ojai Valley Inn) to hide out at when you want to escape the LA madness.
    Suggested by @mandi