Ooh! I love these kind of threads! 
1. What's your standard lineart brush?
I use Photoshop CS6 and I managed to buy Kyle T. Webster's Mega Pack Brush Set before it became PS CC exclusive, and after I got it I swear by them and haven't really used anything else since. So for line art i use Kyle's Chisel brushes.
Here's an example
and I made a version without colour so you can better see the lineart 
2. Do you use anything special for backgrounds?
I use the same brush for characters and environments, I just vary the brush size depending on how close something is to the "camera". The closer it is, the thicker lines and vice versa (The 10 and 35 px ones I made myself).
3. Do you use pen/pencil dynamics when doing lineart?
Eh... Shape dynamics? I honestly don't know, I'm not good with all the fidling with those dynamics, which is why I use already made brushes, and then modify a bit if needed...