My config

configuration.nix

# Edit this configuration file to define what should be installed on
  # your system.  Help is available in the configuration.nix(5) man page
  # and in the NixOS manual (accessible by running ‘nixos-help’).

  { config, pkgs, ... }:

  {
    imports =
      [ # Include the results of the hardware scan.
        ./hardware-configuration.nix
      ];

    boot.loader = {
      efi.canTouchEfiVariables = true;
      gummiboot.enable = true;
    };
    
    networking = { 
      hostName = "Mjolnir"; # Define your hostname.
      hostId = "<redacted>";
      networkmanager.enable = true;
    };

    # Select internationalisation properties.
    i18n = {
      consoleFont = "sun12x22"; # "ter-132n";
      consoleKeyMap = "no-latin1";
      defaultLocale = "nb_NO.UTF-8";
    };

    time.timeZone = "Europe/Oslo";

    users.extraUsers.thor = {
      isNormalUser = true;
      extraGroups = ["wheel" "audio" "video" "networkmanager"];
      uid = 1000;
    };
    
    # Enable the X11 windowing system.
    services = {
      # To show the manual in one of the terminals
      nixosManual.showManual = true;
      acpid.enable = true;
      # Disable NTP, enable chrony...
      ntp.enable = false;
      chrony.enable = true;
      # Setup X
      xserver = {
        enable = true;
        layout = "no";
        videoDrivers = [ "intel" ];
        vaapiDrivers = [ pkgs.vaapiIntel ];
        displayManager.lightdm.enable = true;
        desktopManager.kde5.enable = true;
        desktopManager.kde5.phononBackends = [ "vlc" ];
        deviceSection = ''
          Option      "AccelMethod"  "sna"
          Option      "TearFree"  "true"
        '';
        displayManager.sessionCommands = ''
          # Map left superkey to left ALT+F1
          xcape -e "Super_L=Alt_L|F1"
        '';
        synaptics = {
          enable = true;
          twoFingerScroll = true;
          #buttonsMap = [1 2 3];
        };
        startGnuPGAgent = true;
      };
      quassel = {
        enable = true;
        user = "thor"; 
        dataDir = "/home/thor/.config/quassel-irc.org/";
      };
      # Install standard network services
      samba.enable = true;
      geoclue2.enable = true; 
      minidlna.enable = true;
      avahi.enable = true;
      # ...and a guardian at the gate
      fail2ban.enable = true;
      locate.enable = true;
      # Gotta be kind to your eyes...
      redshift = { 
        enable = true;
        # Bergen, Norway
        latitude = "60.397076";
        longitude = "5.324383";
        temperature.night = 2500;
      };
    };
    
    programs.bash.enableCompletion = true;
    programs.ssh.startAgent = false;

    fonts = {
      enableFontDir = true;
      enableGhostscriptFonts = true;
      fonts = with pkgs; [
        corefonts  # Micrsoft free fonts
        inconsolata  # monospaced
        ubuntu_font_family  # Ubuntu fonts
        terminus_font # for hidpi screens, large fonts
        liberation_ttf
      ];
      fontconfig.dpi = 192;
    };
    
    # Nixpkgs bulid options
    nixpkgs.config = {
      allowUnfree = true;
      firefox = {
       enableGoogleTalkPlugin = true;
       enableAdobeFlash = true;
      };
    };
    
    # List packages installed in system profile. To search by name, run:
    # $ nix-env -qaP | grep wget
    environment.systemPackages = with pkgs; [
      firefoxWrapper
      wget git sudo nodejs terminus_font gpgme xcape
      #?Missing dependency for optimus?#
      virtualgl
      #KDE 5.2
      plasma52.baloo plasma52.breeze-qt4 plasma52.breeze-qt5 plasma52.kde-cli-tools plasma52.kde-gtk-config plasma52.kdecoration 
      plasma52.kdeplasma-addons plasma52.kfilemetadata plasma52.khelpcenter plasma52.khotkeys plasma52.kinfocenter plasma52.kio-extras 
      plasma52.kmenuedit plasma52.kscreen plasma52.ksshaskpass plasma52.ksysguard plasma52.kwayland plasma52.kwin plasma52.kwrited plasma52.libbluedevil 
      plasma52.libkscreen plasma52.libksysguard plasma52.libmm-qt plasma52.milou plasma52.muon plasma52.oxygen plasma52.oxygen-fonts plasma52.plasma-desktop 
      plasma52.plasma-nm plasma52.plasma-workspace plasma52.plasma-workspace-wallpapers plasma52.polkit-kde-agent plasma52.powerdevil plasma52.sddm-kcm plasma52.startkde 
      plasma52.systemsettings quassel_qt5
      # KDE 5.1 apps
      kde5.amor kde5.analitza kde5.ark kde5.attica kde5.audiocd-kio kde5.baloo kde5.blinken kde5.bomber kde5.bovo kde5.breeze-qt4 kde5.breeze-qt5 kde5.cantor kde5.cervisia kde5.dolphin-plugins kde5.dragon kde5.extra-cmake-modules kde5.ffmpegthumbs kde5.filelight kde5.frameworkintegration kde5.granatier kde5.gwenview kde5.jovie kde5.juk kde5.kaccessible kde5.kactivities kde5.kajongg kde5.kalgebra kde5.kalzium kde5.kamera kde5.kanagram kde5.kapidox kde5.kapman kde5.kapptemplate kde5.karchive kde5.kate kde5.katomic kde5.kauth kde5.kblackbox kde5.kblocks kde5.kbookmarks kde5.kbounce kde5.kbreakout kde5.kbruch kde5.kcachegrind kde5.kcalc kde5.kcharselect kde5.kcmutils kde5.kcodecs kde5.kcolorchooser kde5.kcompletion kde5.kconfig kde5.kconfigwidgets kde5.kcoreaddons kde5.kcrash kde5.kcron kde5.kdbusaddons kde5.kde-base-artwork kde5.kde-baseapps kde5.kde-cli-tools kde5.kde-l10n-ar kde5.kde-l10n-bg kde5.kde-l10n-bs kde5.kde-l10n-ca kde5.kde-l10n-ca_valencia kde5.kde-l10n-cs kde5.kde-l10n-da kde5.kde-l10n-de kde5.kde-l10n-el kde5.kde-l10n-en_gb kde5.kde-l10n-es kde5.kde-l10n-et kde5.kde-l10n-eu kde5.kde-l10n-fa kde5.kde-l10n-fi kde5.kde-l10n-fr kde5.kde-l10n-ga kde5.kde-l10n-gl kde5.kde-l10n-he kde5.kde-l10n-hi kde5.kde-l10n-hr kde5.kde-l10n-hu kde5.kde-l10n-ia kde5.kde-l10n-id kde5.kde-l10n-is kde5.kde-l10n-it kde5.kde-l10n-ja kde5.kde-l10n-kk kde5.kde-l10n-km kde5.kde-l10n-ko kde5.kde-l10n-lt kde5.kde-l10n-lv kde5.kde-l10n-mr kde5.kde-l10n-nb kde5.kde-l10n-nds kde5.kde-l10n-nl kde5.kde-l10n-nn kde5.kde-l10n-pa kde5.kde-l10n-pl kde5.kde-l10n-pt kde5.kde-l10n-pt_br kde5.kde-l10n-ro kde5.kde-l10n-ru kde5.kde-l10n-sk kde5.kde-l10n-sl kde5.kde-l10n-sr kde5.kde-l10n-sv kde5.kde-l10n-tr kde5.kde-l10n-ug kde5.kde-l10n-uk kde5.kde-l10n-wa kde5.kde-l10n-zh_cn kde5.kde-l10n-zh_tw kde5.kde-runtime kde5.kde-wallpapers kde5.kde-workspace kde5.kdeartwork kde5.kdeclarative kde5.kded kde5.kdeedu-data kde5.kdegraphics-mobipocket kde5.kdegraphics-strigi-analyzer kde5.kdegraphics-thumbnailers kde5.kdelibs kde5.kdelibs4support kde5.kdenetwork-filesharing kde5.kdenetwork-strigi-analyzers kde5.kdepim kde5.kdepim-runtime kde5.kdepimlibs kde5.kdeplasma-addons kde5.kdesdk-kioslaves kde5.kdesdk-strigi-analyzers kde5.kdesdk-thumbnailers kde5.kdesignerplugin kde5.kdesu kde5.kdewebkit kde5.kdf kde5.kdiamond kde5.kdnssd kde5.kdoctools kde5.kemoticons kde5.kfilemetadata kde5.kfloppy kde5.kfourinline kde5.kgamma kde5.kgeography kde5.kget kde5.kglobalaccel kde5.kgoldrunner kde5.kgpg kde5.kguiaddons kde5.khangman kde5.khelpcenter kde5.khotkeys kde5.khtml kde5.ki18n kde5.kiconthemes kde5.kidletime kde5.kig kde5.kigo kde5.killbots kde5.kimageformats kde5.kinfocenter kde5.kinit kde5.kio kde5.kio-extras kde5.kiriki kde5.kitemmodels kde5.kitemviews kde5.kiten kde5.kjobwidgets kde5.kjs kde5.kjsembed kde5.kjumpingcube kde5.klettres kde5.klickety kde5.klines kde5.kmag kde5.kmahjongg kde5.kmediaplayer kde5.kmenuedit kde5.kmines kde5.kmix kde5.kmousetool kde5.kmouth kde5.kmplot kde5.knavalbattle kde5.knetwalk kde5.knewstuff kde5.knotifications kde5.knotifyconfig kde5.kolf kde5.kollision kde5.kolourpaint kde5.kompare kde5.konquest kde5.konsole kde5.kopete kde5.kparts kde5.kpat kde5.kplotting kde5.kppp kde5.kpty kde5.kqtquickcharts kde5.krdc kde5.kremotecontrol kde5.kreversi kde5.krfb kde5.kross kde5.kruler kde5.krunner kde5.ksaneplugin kde5.kscd kde5.kservice kde5.kshisen kde5.ksirk kde5.ksnakeduel kde5.ksnapshot kde5.kspaceduel kde5.ksquares kde5.kstars kde5.ksudoku kde5.ksysguard kde5.ksystemlog kde5.kteatime kde5.ktexteditor kde5.ktextwidgets kde5.ktimer kde5.ktouch kde5.ktuberling kde5.kturtle kde5.ktux kde5.kubrick kde5.kunitconversion kde5.kuser kde5.kwallet kde5.kwalletmanager kde5.kwidgetsaddons kde5.kwin kde5.kwindowsystem kde5.kwordquiz kde5.kwrited kde5.kxmlgui kde5.libkcddb kde5.libkcompactdisc kde5.libkdcraw kde5.libkdeedu kde5.libkdegames kde5.libkeduvocdocument kde5.libkexiv2 kde5.libkface kde5.libkipi kde5.libkmahjongg kde5.libkomparediff2 kde5.libksane kde5.libkscreen kde5.libksysguard kde5.libmm-qt kde5.libnm-qt kde5.lokalize kde5.lskat kde5.marble kde5.milou kde5.mplayerthumbs kde5.okteta kde5.okular kde5.oxygen kde5.oxygen-fonts kde5.oxygen-icons kde5.pairs kde5.palapeli kde5.parley kde5.picmi kde5.plasma-desktop kde5.plasma-framework kde5.plasma-nm kde5.plasma-workspace kde5.plasma-workspace-wallpapers kde5.powerdevil kde5.poxml kde5.print-manager kde5.qt5 kde5.rocs kde5.solid kde5.sonnet kde5.startkde kde5.step kde5.superkaramba kde5.svgpart kde5.sweeper kde5.systemsettings kde5.threadweaver kde5.umbrello
    ];
  }