OneNote sounds like a good choice, you can write in it by hand, as I
mentioned it does a credible job converting to text. You can sketch, copy
and paste, and it's good for organizing, with as many tabs as you want.
Kind of like a DayPlanner book.
The 2007 version is much improved, I've not yet really dug into it.
FWIW, students at the university where I teach have been using tablets for a
year now, and a great number of use OneNote with great success.