When I install Linux I go step by step through the directories in my ~/.config dir copying over my backup files so that all my app's are just as I had them before on my last install. Saves a lot of time, and it can be done even before installing all the apps that need a config directory.
! back up your new ~/.config dir first if you like!
I also build up a set of config files for copying over to Linux systems that I install on other people's PC's.
In ~/ I backup: .fonts, .kde, .mplayer, .sword, .xnviewmp, .xiphos
In ~/.config: audacious, chromium, clipit, libreoffice, lxpanel, lxsession, lxterminal, openbox, pcmanfm, sunflower, thunar, xfce4, xfe
In ~/.local/share you have .desktop files for the menu if you made changes there and marble map images if you use that.
Files I migrate/tweak for LXDE installs
I have a config file backup script to undertake the job for me (LXDE)
cp ~/.config/libreoffice/4/user/registrymodifications.xcu ~/Settings/LO\ macro/
cp ~/.config/openbox/* ~/.config/lxterminal/lxterminal.conf ~/.config/pcmanfm/LXDE/pcmanfm.conf ~/Settings/OB-lxde/
cp ~/.config/lxpanel/LXDE/panels/* ~/Settings/OB-lxde/panels/
cp ~/.config/ranger/* ~/Settings/ranger/
cp ~/.config/Thunar/* ~/Settings/thunar/
cp ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-power-manager.xml ~/.config/xfce4/xfconf/xfce-perchannel-xml/thunar.xml ~/.config/xfce4/xfconf/xfce-perchannel-xml/thunar-volman.xml ~/.config/xfce4/xfce4-notes.gtkrc ~/Settings/xfce/
cp ~/.kde/share/apps/k3b/k3bui.rc ~/Settings/kde/apps-k3b/
cp ~/.kde/share/config/k3brc ~/.kde/share/config/kdeglobals ~/kdenlive/.kde/share/config/kdenliverc ~/Settings/kde/share-config/
cp ~/.luckyBackup/profiles/* ~/Settings/lucky\ backup/
cp ~/kdenlive/.kde/share/apps/kdenlive/kdenliveui.rc ~/Settings/kde/apps-kdenlive/
cp -r ~/scripts/* ~/Settings/scripts/
cp ~/.bash_aliases ~/.bashrc ~/.compton.conf ~/.gtk-bookmarks ~/.gtkrc-2.0 ~/.gtkrc-2.0-gnome-color-chooser ~/Settings/HOME\ files/
lines 2 &3 swap for these if openbox no lxde:
cp ~/.config/openbox/* ~/.config/lxterminal/lxterminal.conf ~/Settings/OB/
cp ~/.config/lxpanel/OB/panels/* ~/Settings/OB/panels/