Actually the more I use the 770 the more I am impressed to its capabilities outside of book reading. It picks up any free wi fi available on the go and it's quite fast browsing. Also there are many applications you can install from Maemo, all wireless if you have a wi fi router at home, no need to use the USB. When I buy a drm free book from Baen or Fictionwise say, I download the prc zipped or not directly on 770, in the appropriate folder on the memory card. And you can do this with Gutenberg and so on.
On the other hand since I got the Sony with the cc offer, I am getting more and more impressed with it too; converted 60 or so books to lrf in addition to 2 I got using part of the credit, since I found it the best format (used lit2lrf from libprs500 for Baen/Fictionwise and anything I have in lit format among others, and the makelrf from txt files for the rest since it's fast and has very nice output) Also the other nice thing is that all 60 novels in lrf format took about 40 MB so I can put 50 MB more of books if I want.
I intend to get a 2GB card to put scientific books on it (the best output I found is to use pdfread to convert from djvu/pdf to lrf and then use the half page feature, though for some djvu's I've tried, jap works nicely too)
So again, get both too if you can afford it.