I'm a fan of C-n and C-p; I often find myself using them even in Sublime Text or other editors (even in a text area on a web page). But for some reason I find C-f and C-b much more obtuse. Part of it is that in a QWERTY layout, "f" is to the left of "b", and yet "f" moves the cursor to the right. Also, assuming you press Ctrl with your left hand, "f" is more natural to use with your left hand, while "b" is a bit of an awkward reach, making it natural to use the right. This left-right switch is awkward, especially combined with the aforementioned direction reverse.

On the other hand, C-a and C-k (especially in combination with each other) and C-e are incredibly useful, and once I discovered them I immediately started using them everywhere.