Can't forget about the Mac users right?
I have personally tested all these toolkits on my Nexus 5. They are confirmed working!
What Can This One-Click Mac Toolkit Do?
Root Nexus 5
Install TWRP Recovery on Nexus 5
Unroot Nexus 5 to Stock Android 5.0.1 Lollipop!
Download all the Mac toolkits here:
Q: I want to root my Nexus 5, do I need to download each part of the toolkit separately?
A: No, all you need to do is download the root toolkit. That toolkit will unlock your bootloader, install TWRP, and root it.
December 27th 2014:
Toolkits updated for Lollipop support
November 6th 2013: