StackOverflow seem to have become my dedicated C# documentation source, but ive never needed to register an account there. Whenever I type "How to XYZ in C#" into google, the top result is always a StackOverflow page where someone's already asked the same question :-)

Basically the same here. I don't have an account at StackOverflow and apparently I don't need one.

Search in Bing, check first 4 results, usually they will be stack overflow but for graphics / gaming it is best to check GD.net first

GD.net is great for all graphic / game related issues, you can guarantee the question has been answered or will get answered here, for everything else though Stack Overflow seems to be a better choice, or at least has the questions answered.

Not sure about other forums but if you have a graphics / game related issue, it is better to check here first.

For libraries / language specific stuff it is best to keep an eye on the forum dedicated to that library / language as well keeping an eye on GD.net / Stack Overflow depending on what the problem is.

Im talking about stackoverflow. Everybody there just seems hostile and eager to tell you how bad you are. The fast responses are what keeps me asking questions there though

I've started to use StackOverflow more, but it's not the best place to ask questions like "my code is broken how do I fix it?" If I have a "my code is broken how do I fix it" type of question, I usually ask it here on GameDev.net. If I have a more Q&A style question, especially one that digs into language standards, I ask it on StackOverflow instead of here.

Actually I think you said it best and thats what I've learned after using both of these sites. I spend about 95% of my time here, 3% googling answers, and 2% on stack.