external hhd's are very good for backup, but forgetting to format can be a royal pain and loss of data. i have everything on every hhd backed up to DVD's. when i finally can afford the blue ray burner, i wont have so many discs.
as far as ripping goes, the time takes as fast as your processor and memory can handle..and it helps to make sure there isnt smudges or scratches from the cd your ripping.