I'm considering purchasing an iPad to inaugurate the start of my PhD program beginning in Fall. I'm wondering if the iPad would make a useful tool for a graduate student. Here are the circumstances: I currently use a MacBook with a suite of DevonThink, Sente, Pages, Mellel and Skim to do pretty much everything I need done for my studies. I also study Japanese, but for that I mostly use a couple dictionary apps on my iPhone 3g and occasionally the dictionary built into Leopard. The most important question is whether the iPad offers a program that allows the highlighting of PDFs. Currently when I highlight PDFs in Skim, I can move those to DevonThink and the highlighting will be preserved. I know Sente for the iPad allows highlighting but I haven't been able to figure out of that highlighting is preserved in other PDF readers. Are there any other grad. students or academics out there or even Japanese language learners who have made use of the iPad and feel it is worth the investment (on a graduate student budget)?