(edit): Looks like it's nearly unanimous. Here's a picture for folks who haven't been there: http://nycpano.files.wordpress.com/2011/03/rose-reading-room...
NYPL: Science, Industry and Business Library (SIBL)
188 Madison Avenue @ 34th Street
(917) 275-6975
If it's warm out and you don't need internet access, I'm also a big fan of working from the High Line. There are lots of shaded tables, and you can't beat the ambiance. If you need to duck away for power or WiFi, Chelsea Market has both nearby (although getting a place to sit at Chelsea Market can be tough if it's after 11am or so).
Convenient outlets at most seats, free wifi, and a Stumptown adjoined!
Lot's of creative types working there, illustrators, writers and such. Can get pretty busy after 5pm.
http://www.fastcompany.com/1768472/ace-hotels-communal-works...
20 West 29th Street New York, NY 10001
* The wifi might be free, but you need a passcode. Do you get this by ordering something?
* The prices are pretty exorbitant. Coffee, tea, and sodas are $4, and $20 for a glass of wine.
* Pretty dark inside. OK for working on a laptop, not so good for writing anything by hand.
Also, I wouldn't say that $4 for coffee that good is exorbitant. To each their own I suppose.
- Cafe Amrita, near 110th St and Central Park West. Generally has a pleasant buzz. I've noticed other techie types there, but not tons. They kick out the laptop crowd out on weekends, and at night they become more of a bar.
- Tea Spot, near MacDougal and West 3rd in the Village. A smallish place that has always been pretty quiet when I've worked there. NYU students are most of their customers, I reckon.
- Cosi near 23rd st and 6th Ave, in Chelsea. This is a chain, but this particular Cosi is well-lit, has good internet service, is large, and never seems to be very busy.
- As others have noted, New York Public Libraries are often great places to work. I sometimes sneak off from my office to use the Hudson Park Library, which is near Leroy and 7th ave in the Village. Its a tiny little branch library, but its quiet and the internet service is fast. There's a lot of little branches like that, look on the web site for locations.
In Manhattan it can be a little challenging to find a coffee shop to set up in for very long. Seats and outlets are at a premium and many are policing wifi moochers these days. There are a few large starbuckses with a good amount of room though. I've also worked at the library before (not many outlets, and you can't take phone calls inside).
In Williamsburg there are a ton of work-friendly coffee shops. If you take the L train to the bedford, lorimer or graham stops, pop open Yelp and you'll spot at least 3-4 coffee shops in a 5 block radius of each, with wifi and (usually) seats...
I suggest the Science, Industry and Business Library (SIBL) on 34th and Madison (http://www.nypl.org/locations/sibl). They have a big room full of about 150 workspaces to work from your notebook with power, Wifi and Aeron chairs. I've been there several times and did not run into any issues with finding an open seat.
There's seating and the light isn't too harsh for being fluorescent. I've seen people go there without their own computers and basically look as if they're editing video for a project...and the staff pay no mind.
Don't know what they'd say if you planted a dell laptop on one of the unused Genius bat areas, though
While I'm on the topic, the Apple stores in SoHo and in UWS have comfortable theater seating. I've planted myself there and even if you don't have headphones, the Apple Genius giving a walk through of how to use Keynote/iCloud/whatever makes for decent background noise
- Kaffe 1668 in Tribeca - great atmosphere, great coffee & tea
- Cafe Mercato on Broadway at Bleecker St. - open 24h, it's a sizeable deli, has tap beer, and work space in the back
- Ace Hotel lobby on W. 29 st - classy but gets very crowded
Brooklyn:
- Vineapple in Brooklyn Heights - coffee & grilled cheese
- Tea Lounge in Park Slope - coffee & beer & many couches
Also, if you're anywhere near Fort Greene, Smooch is a pretty awesome coffee shop.
Also, the New York Public Library is right nearby, so if you get annoyed by crowds or weather, you can relocate to one of the most beautiful quiet workplaces in the entire city.
http://www.panix.com/~melling/nyc/
The Google spreadsheet for the "Public Works Spaces" is here:
https://docs.google.com/spreadsheet/ccc?key=0AphQpsbOUWiedDV...
Everyone should feel free to add to the spreadsheet.
P.S. I know NYU Poly DUMBO has open space, it's in an awesome area, and the management there is friendly.
1. A quiet place where you can bang out work (e.g. libraries)
2. Somewhere with more of a scene where you can work and also mix with others in the startup / tech ecosystem (e.g. GA, Ace)
3. Somewhere like #2 but with a little more NYC flavor and less tech (e.g. Kaffe 1668)
I guess having people say "my company started from humble beginning in the local Starbucks" is no longer valuable to them.
Very handy if you want to just stay somewhere warm and work in middle of night.
In Brooklyn... reBar in DUMBO has free wifi, though it's more of a bar but seems pretty dead on weekdays.
It's open 9-5 every day near Union Square. Has coffee and decent chairs, though can get a little loud.
Cocoa Bar on Clinton btw Stanton and Houston is great