In my case, I have used a desktop, a laptop and a smartphone (I have only used a tablet pc to see how my blog looks on it, but I have never composed any article on it).
As usual, the preference will vary with each blogger.
Which electronic device do you use to blog on? And if you are into the habit of using multiple devices, which one of them do you prefer? I would LOVE to read your answers (And I am sure that my readers would like to peruse your answers as well).