If you want notification ringtones as well, you can create a folder called "Notifications" for them. They do not have to be on the root of external storage - I have a folder called "Media", with folders called "Ringtones" and "Notifications" in that folder.
Also, the folders can be on the sdcard-ext, as Thom references it - this is the physical SD card; confusingly, sdcard is actually internal storage.