Hello, peeps!
I had a laptop laying around and I thought I’d give NixOS a spin because it looks pretty interesting.
I am still trying to find my way around, though, so the first “issue” I’ve encountered is how to uninstall some packages that come preinstalled with GNOME. I have looked through the configuration.nix and tried to follow the instructions provided in this link but to no avail.
How can I uninstall packages (and how can I list installed packages)?
-Cheers! 
For listing installed packages using nixos-option command to get value of environment.systemPackages might be helpful.
As for removing, we have a PR that will document this behaviour but it has not been merged yet:
Though that is not completely up to date. evince, geary and some other modules can be excluded that way now.
Thanks for the reply. So, in other words, I would have to exclude the packages upon installing the system? E.g. if I want to uninstall cheese, I’d have to opt-environment.gnome3.excludePackages = [ pkgs.gnome3.cheese ];? Never mind; that didn’t work.
Does it mean that I need to disable all optional packages?
I would expect cheese to be disabled by that. Also you can disable whole groups of programs, see the module code:
Perfect. Thanks a lot, Jan. I did manage to find a way around it, though: disabling the packages after install worked a charm 