PDF import into Endnote is only cumbersome if you have several thousand to do "after the fact". What you do is tile an endnote window and a file manager side by side. Then you just drag the pdf onto the title of its entry Endnote and it is automatically copied to the Endnote managed folder and a link created to it. It's not too cumbersome if you do it as you download/save pdfs. Of course, it would be preferable, if you are having Endnote manage the pdfs to save the pdfs directly to Endnote, but I've yet to see that as an option. Alternatively, you can simply have a link created that points to wherever you happen to have the pdf stored. This functionality was introduced several versions back... As I noted above, if I had had my head screwed on right I would have realised that having Endnote store the pdf's is silly given the size of even a small library of pdfs and that v.9 already did all that I needed...
The soft-link to your pdf's is preferable because it allows you to organise your pdfs - I had mine very organised - my folder structure goes: PDF - Journal - Year and in some cases Volume. All pdf's were saved with file names that reflect the title of the work (if I was starting again I'd put author name first, year of publication and then the title, but can't go back 7 years, sadly. Endnote just dumps the pdfs into it's own folder in a common folder under the library folder. So, Endnote libraries - Library Name.data - PDF. Fortunately, desktop search technology and/or Endnote's own system mean that nothing is far from "hand". I have found this sort of liberating because occasionally I'll just save the pdf with its default name (science.pdf or article.pdf or 012387.pdf) and don't have to worry about finding it again.
Now, to get to NoD5's point finally (if I am getting it) - it would be great to have an app like Endnote scan a pdf and extract the information from it to generate the Endnote entry. I know that this would SERIOUSLY increase the size, complexity and footprint of Endnote, but it would be useful. If free search agents can scan a pdf in under a second and catalogue its content, surely an app could extract data from it to insert into a database. Of course, this would require some sort of standardised formatting on the part of publishers and authors OR the creation of some sort tag that contains the info (a la mp3s). Fortunately, most publications now have a "download citation" feature and will auto insert everything into a new Endnote library entry. Sweet. Now if we could just save a pdf directly to Endnote...
Surfulater looks interesting - this kind of functionality is frequently requested for
TexNotes/Do-Organizer, but it's been pointed out that this would significantly increase the size of the database. The developers have promised to consider it but so far nothing as come of it (at least with TexNotes - I've not really been following Do-Organizer's development). Anyway, my point being that this would be a useful feature. The issue is with portability - if one is not concerned about that, then it's not an issue.