My ereader of choice is the Pocketbook 360, I carry it around everywhere as it's the most pocketable of the three.
My second choice would be my Kobo - it only supports epub files and it's a tad large, so I use it when reading in the comfort of my home.
Finally, my trusty old Rocket eBook is resting in a drawer. I can't convince myself to part with it, I have so many wonderful memories...
