Tablet PC's
I too have been using a Tablet PC for about a year. Quickly adopted it as my only computer. Got rid of the desktop computers, implemented GtD in the little Franklin-Covey application. TabletPlanner is slower than OneNote, but better geared towards moving discrete tasks and projects around.
For GtD I could do it on paper just as easily as I do it on a computer, and did, but it takes a lot more space, and is more difficult to manage on paper. I tavel a lot, and the Tablet has replaced an awful lot of paper, gizmos, laptops, desktops, etc.
I like using handwriting on the Tablet, and convert almost nothing to into straight text.
It's kind of Zen-like! A giant assortment of 'stuff' now resides in an 1"x12" box. And yes, I have a backup unit in a drawer, awaiting the inevitable hardware failure.