Recommended e-reader for network/sysadmins?

To be more specific, I have been carrying around textbooks for Red Hat, DNS, JunOS, Cisco, ITIL, C, Perl, etc... and I think it's time to make the switch to digital.

I need the ability to download PDFs from the net and read them, as well as download/purchase new textbooks and manuals. I would also be very interested in having access to a lending library of some sort.

EDIT: I'm pretty well sold on the 4th gen Kindle @ $79. I was considering the Touch 3g version but it doesn't support landscape mode so scratch that; PDFs are high on my list and many require landscape mode.

EDIT: I've read some compelling arguments against e-readers for reference material. Will check out a few tablets designed for pdf.