I tried code:blocks IDE and I am very happy with it!
I has (nearly) everything for lazy people like me:
Source browser , find /replace in files , project manager, plug ins, shortkeys , codeformatter etc.
I tried Epsylon but this is very heavy stuff, it takes half an hour to start.
Until now I used KamAVR (great too!) but it lacks the above functions and it is not maintained anymore.
A nice thing is that the makefiles generated by KamAVR (the .kmk files) can be used as external make file.
Configuration is easy: set Project->properties to "external makefile" , ignore other things like default compiler, it's all in the makefile.
Set the project -> build options -> make command to $make -f $makefile
Settings -> global compiler settings -> programs : set installation directory to the WinAVr dir and the compiler exe to avr_gcc , make exe to the WinAvr make in the utils / bin dir ,additional path to winavr/utils/bin.