Tops on my feature wishlist are:

E-reader in landscape This will allow a laptop-style orientiation, typing/browsing on the bottom portion and having a document open in landscape mode the e-reader screen. It will also facilitate magnification of PDFs and facilitate reading some wider content.

Support for cell phone tethering via USB or bluetooth Since the eDGe has USB (and eventually Bluetooth) but lacks 3G and many of us have tethering-capable phones (iPhone, Nexus One, etc) this would seem like a great way to allow the eDGe to benefit from a 3G internet connection when WIFI is not available.

MsExchange email support: Essential for me as a business user. Sync with Exchange calendar, contacts, and tasks would go a long way to make this a business-friendly device as well.