Where are the tastiest bakeries in SF?

Ah, Melissa! I started salivating just thinking about answering your question, as there are so many delicious bakeries here in the city. I recommend the following:

• Tartine bakery This Mission hotspot is famous for a reason! Their desserts are impeccable, and the bread pudding is among the best I've ever had.
  
  
• SusieCakes My favorite cupcakes in the city, plus slices of cake the size of your face. SusieCakes isn't limited to San Francisco (there are others in California), but I do recommend treating yourself to a piece of the celebration cake when you're here.
  
  
• Le Marais Bistro and Bakery Fairly new to the Marina, and getting tons of hype. This little french spot is full of tasty treats, and is generally pretty easy to get into.
  
  
• B. Patisserie The line can be long and moves fast, allowing you reasonably quick entry into pastry heaven.
  
  
• Boudin Bakery feels a bit more generic, but really does have some amazing sourdough. 
  
  
• Craftsman and Wolves Though known for the "Rebel Within" (muffin with an egg inside), the bread and baked goods are divine. Make a day of it by checking out some of the nearby shops on Valencia St.
  
  
• Devil's Teeth Baking Company This sunset shop has amazing cookies, bars, pies, scones and breads. It's also only a couple of blocks away from Ocean Beach and close to the entrance of Golden Gate Park, so a to go bag is a great idea. ;)
  

Hope this helps!

Ooooooh Melissa you are in for a treat! It just so happens that my favorite bakery is located in San Francisco and you must, must, MUST treat yourself here.

Let me tell you about a magical little place called Thorough Bread and Pastry. I think what I love here the most (besides all their sweet goodness) is that they remain consistent in terms of freshness and quality. Not embarrassed to admit i've tried everything here. Twice. 

Some notable treats: I know everyone has been on a macaron hype lately but they have the fluffiest ones here, you won't be disappointed. I usually DESPISE carrot cake...except theirs. The sticky bun with a cup of coffee I guarantee will make your day. And the almond croissant is just out of this world. Liiiiiight and fluffy. 

Go. Go now. 

I mean Krista below really nailed it. Tartine bakery may just be my favorite. Their morning buns are so freakin' good, as is everything else they do. Boudin Bakeryis touristy and everyone and their momma knows about it, but what they do (sourdough), they really do well. 

Another bakery I'll mention is Arizmendi Bakery. It comes from the same folks that do one of my favorite pizza spots, Cheese Board Bakery & Cheese in Berkeley. No frills bakery, but great baked goods, as well as some good pizza.

But if you go nowhere else, go to B. Patisserie. It's worth it, really.

Don't miss Tartine bakery. 

I have 3 SFgems that you should check out without question:

- The Pomme d'amore at Knead Patisserie.  It's as if a creme brûlée had a baby with salted caramel and a croissant.

- The Kouign-Amann at B. Patisserie.

- Worth the wait because they're fresh out of the oven Hong Kong style egg custard tarts at Golden Gate Bakery.  Eat it right away.  Call to make sure they're open because they'll take a day off just because they can.

One place that I haven't checked out yet, but have been hearing a lot of hype about is the Cruffin at Mr. Holmes Bakehouse

Have fun and call me when you go because I want some

 too :)

It's been said many times, but you'd be missing out if you don't get to B. Patisserie.  Belinda arguably makes the best viennoiserie in the country.

For recommendations not already covered above, I'd also suggest:

Liguria Bakery - super old school foccacia, and an amazing flame throwing oven.

Sandbox Bakery Uniquely Japanese Bakery in a super fun neighborhood (Bernal Heights).  If you catch them at the right time, they also have savory snacks that are delicious.

DeLise dessert cafe if you want something different.  Asian-Fusion (in the original and best sense of the word) baked goods and ice-cream that they make themselves.

Biscuit Bender - Ferry Building stand with everything in Biscuit form

And since you asked about pastry chefs... really quickly, some of my favorites are:

Aster in the Mission, which just opened, has Sean Ehland, who is previously of McCrady's in Charleston.

Bill Corbett of the Absinthe Group makes all manner of delicious things for their restaurants

Melissa Chou of Mourad and Aziza is a hero of SF pastry.

Commis would be a great meal to have both fantastic bread as well as pastries.  Also one of the most affordable fine dining options around

Further afield, there's Bouchon Bakery, Manresa Bread (also just opened), Downtown Bakery & Creamery Della Fattoria Downtown Café, Firebrand Artisan Bread  All of which have their own specialties worth seeking out.  The latter three can often be found at either Bi-Rite Market or at the Ferry Building Saturday AM Farmer's Market

Fire hose, I know...but the bay area's got a pretty strong bakery/pastry game right now!

Try Craftsman and Wolves and Tartine bakery

Tartine bakery is a foodie haven. Be prepared to wait in line, though. They not only have baked goods but delicious lunch options, as well. 

Devil's Teeth Baking Company is by Ocean Beach. It is worth the trek! I highly recommend the breakfast sandwich (on a homemade biscuit). 

The Mill has amazing fresh bread made by the famous Josey Baker. They also make pizza on most Mondays and Fridays. The crust is fantastic! 

Although it is supertouristy, North Beach (California) has numerous, high quality Italian style bakeries. Caffe Greco has amazing, freshly made-to-order cannoli. La Victoria is over 100 years old with great biscotti. It is a super walkable area and very lively. 

Boudin Bakery has delicious flourless peanut butter cookies and chocolate covered macaroons. Yes their sourdough bread is excellent, authentic, baked here for 150+ years.. 

 Finally San Francisco Chinatown has famous, authentic bakeries. There is always a long line out the door for egg custard tarts at Golden Gate Bakery. If you are a foodie in general, it's fun to walk Stockton St. 

Indulge yourself and have a great time.

I just tried B. Patisserie last night.  It is spectacular.  The chef trained with Pierre Herme' in Paris, and IMHO (and in the opinion of many many critics too) Mr. Herme' is the best baker in the world.  B Patisserie is the real deal.  It is again in IMHO the only place in the USA one can get a decent french macaron (only available on weekends and tip - wait 20-30 minutes for it to come to room temp before eating it as they keep them cold, it makes a big difference in flavor and texture), and they make a Koign Aman that makes your knees weak.  It's by far the best in SF and certainly the best in CA.  

Mr. Holmes Bakehouse - pastries no breads. A brand spanking new bakery that opened up on Larkin (cross street is Sutter st) about a month ago. They have this thing called THE CRUFFIN. You will have to wait in line to get one and they don't start serving them till 9am and they sell out fast.  There's actually a dedicated line just for people who want Cruffins (only sell 2 per person). IT IS WORTH IT :)

All of those are solid, awesome options.  If you can, also add Mr. Holmes Bakehouse and Flour & Co in Nob Hill to your list. Hope you have many Goldilocks moments with the pastries you sample in SF.

I know everyone and their sister is going to recommend Tartine bakery, but I cannot.  It was painfully mediocre and ultimately disappointing.  I will not be returning.