start with Debian stable and add your cutting-edge packages on top, then watch their sources and mailing lists carefully.
Arch and Fedora follow the same conventions so everything on Fedora is where you expect it from Arch (this also makes much of the great Arch wiki applicable directly).
There will always be a soft spot in my heart for Arch, but Fedora is the perfect balance for me. I can't have my work machine getting broken and forcing me to read forums and mailing lists, etc.
[1]: https://discourse.nixos.org/t/automatic-database-schema-upda...
Lots of projects also put out PPAs with frequent releases for Ubuntu, which are ideal if you need the very latest and greatest. Just realize that you're relinquishing root access to every PPA you add, so be very careful whose PPAs you install, and try to limit them to the extent possible (same applies to any apt repo, obviously).