Acer do an 18.4 tablet PC thing and if it's portable, I'd get it. I use an iphone, which is a good phone, but for showing things to clients, it falls short. Laptops are no good. Essentially, I want to be able to toggle between various maps/layers with ease and interact with it readily. For poking around myself, it tends to be A4 snippets I can graffiti. I don't think any tablet app will replace a raw scribble, however many people will go for some sort of palmtop.