PDFs on the iPad

Hi everyone,

I'm currently in college, in which i'm dealing with a lot of pdfs, since I have to read a lot of journal articles, lecture slides, etc. I want to get a good app for reading PDFs that allows me to highlight text, edit, add notes, sync with dropbox, etc.

Which app would you guys recommend? I've been looking at iAnnotate, PDFExpert and Goodreader. For me it's important that when I modify a pdf-file, it will show my modifications and annotations in other pdf-readers as well and it syncs seamlessly with Dropbox. Ease of use is also important, of course. I want to be able to organize my files and put them in separate folders for each course I take or project I'm working on. Please let me know what you guys think.