Emacs with a package on a league of its own: Helm

Why Helm is powerful: An example in jump around Linux kernel source tree interactively: http://tuhdo.github.io/helm-intro.html#sec-28

Helm is capable of a lot. For example, context-senstive code completion in Helm: http://tuhdo.github.io/static/auto_complete.gif . Pay attention to before and after liux/printk.h is included.