Condensed summary of a friendsourced Facebook thread. Here are some options friends recommended for buying a suit in SF:
Indochino
Suit Supply
Thick as Thieves: online
River Island: online
Bonobos
Men's Wearhouse
Goodwill in the DC area because lots of rich politicsmen get rid of a ton of great suits around there
Some place where Tati got her dress (they offered me a discount)
These are all similar price range, $500-800 including tailoring.
(you can also fly to hong kong and get a bespoke suit for a couple hundred bucks, e.g. http://samstailor.com/, which I was really tempted to do.)
I ended up going to that place where Tati got her dress, Indochino, and Bonobos. Didn't go to Suit Supply b/c it's still not open- it's been "opening soon" in SF for approx forever.
That place where Tati got her dress, whose name I forget: is an old-school suit shop. Hugo Boss and stuff. Probably what you'd get at a department store too. Boring, limited styles, expensive. $895 for the one suit that looked kinda good. Skip it.
Bonobos had like one suit to try on. It was fine. Nothing great. Meh.
Indochino seemed pretty solid. They took all my measurements, gave me a million choices. So I bought a suit there.
Some things I learned:
1. your three main options are "off the rack", "made to measure", and "bespoke".
Off the rack is the worst. You just buy a suit. Then they tailor it, but they can only make minor changes.
Bespoke is the best. Some skilled tailor just makes you a suit from scratch, whatever style you want. Probably in the $2k range.
Made to measure is in the middle: suit is made from scratch, but it's to a pre-existing style. (which is fine; you and I are not style pioneers enough to be able to say what we want in a suit.) It's becoming more prevalent thanks to folks like Indochino doing new high-tech stuff. Used to be more expensive but now my Indochino was about the same price as an off-the-rack.
1.5. That said, the tailoring is probably even more important than the suit. Get a good tailor, especially if it's off-the-rack, don't just go to the Macy's etc tailor.
2. Color: Black is cool. Blue makes me look like a businessman. Light colors are not good on me because I have light skin. Pinstripes are for boring businessmen. Grey is ok but just less cool than black.
3. Fabric: Your suit should probably be wool. There's also linen for hot days but it's not as versatile, and it wrinkles. Cotton is starting to be a thing, but probably just get wool.
4. Vest: is not necessary, but it looks cool. And then you can wear the suit in 3 different ways: vest and jacket, just vest, just jacket. Works well with a two-button suit. (if you have a 3-button, you just don't even see the vest b/c your suit comes up higher.) Get 5 buttons - or 7, but 5 is just easier.
5. Buttons: get 2 or 3 or double-breasted, and probably 2. 3 is a little more old fashioned I think, and double-breasted tends to look better on guys who are a bit stouter than me. I guess 1 is also an option? But I think it looks weird.
6. Pants: don't get pleats. Cuffs are up to you, I don't like them, they're more traditional. You want the pants to break on your shoes just once. This means you can go higher and tighter or lower and looser. (either way they'll just hit your shoes once.) Lower and looser is more traditional and won't go out of style as much.
7. Lapels: you can get Notch or Points. Notch is cool. Points is more of a statement.
8. Pick Stitching: makes the suit look more custom, but less formal. We're getting down into the weeds here.
9. If you get it made to measure, you can customize a lot of weird stuff like jacket lining, personalization, etc. So that's nice.
Other references: http://www.artofmanliness.com/2013/09/25/good-fitted-suit-visual/
http://sartorialsin.tumblr.com/