Just Got my new nexus ..wanted to know the process to remove any unwanted apps, or wallpaper, or ringtones??
You can disable apps. Settings > Apps > All (tab at top) > *app* > disable
You may have to uninstall updates prior to disabling an app if it has updated. Be careful what you disable, as it could potentially have a use.
Wallpapers and tones (alarms, notification, ringtones, and UI) that ship with the phone aren't able to be deleted or disabled without root. You can disable the live wallpapers, as they are apps. But the stock wallpapers can't be touched.