Rooting Development Device Is it wise to root my Android phone used for development? Can the device become somewhat unstable which will affect the debugging process when building apps for my phone? 

I have a Galaxy Mega and I'd like to Root the device by using only the most essential utilities that I need (USB Mass Storage, SetCPU, CWM).

I am also wondering if I can apply the usual Samsung Rom Updates by Using CWM and keeping Root, without bricking my device.
Rooting your phone won't in itself make it unstable. It just gives you the opportunity to make it unstable later, by installing apps that interfere with normal system operations, or changing settings that aren't available to end users. If you trust yourself to use root access sensibly, then rooting won't interfere with your development.