Best apps to add to nagios


I hope this is the right place to put this.
I’ve been running nagios for about year now. Its been decided to improve it now so my question is what is the best setup?
I’ve been reading about the add-ons like, nconf, nagiosql, nagiosgrapher, nagvis, pnp4nagios etc.

Does anyone have any suggestions on what works best or pointers to sites. I will be starting from scratch but I have installed nagiosgrapher on the existing system but have got nothing from it.

Many thanks