I want to try out our idea for list-based questions.
So I figured I'd try it here in the Meta.
Please suggest either a single textbook, website, or resource that a user should check before posting here.
This is the obvious one. Most good questions will not be easily answerable with a visit here. But many bad questions ("please explain this basic concept in an excruciating level of detail") could pretty much be answered by copying and pasting from that site.
https://economics.stackexchange.com/search
It's a tired cliche, but people should definitely search this site for similar questions before posting a new one.
Also, newcomers to Stack Exchange should check out our Welcome to Economics.SE! post.
Let's for once "appeal to authority".
MIT has the MIT OpenCoursWare website.
http://ocw.mit.edu/courses/economics/
For micro theory questions:
Mas-Colell, Whinston, and Green (1995): Microeconomic Theory, Oxford University Press, Oxford.
Not everybody should be checking this, of course, but if you are a grad student+ then you should probably own this book. Moreover, since grad school is basically all about learning to figure things out for yourself you should probably at least look in MWG and try to understand what you find there.
That said, some of this material is tricky, so I am okay with questions liek "Eeek! I saw this in MWG and don't understand it."
Mankiw, N. (2012). Principles of Macroeconomics (6th ed.).
I like all three of the Mankiw texts I've read so far, but I thought this one provided a great foundation.