[CentOS] Re-install workstation - best repo's

I'm going to rebuild my workstation because maintaining it is now a nightmare after using "recommended" repo's that now conflict with each other.  Every time I do a yum update I it fails with conflicts.

I'm looking for new recommendations for which repo's to use to have a stable Centos 7 workstation.  Much like Centos itself, most of the web  pages are very old now.

I'm looking for a KDE workstation with mp3 support and video editing.  I use simple command line tools such as ffmpeg.