For a while now, I've been trying not to print out copies of papers I'm using for class. I had a Kindle DX a while back, and I tried loading PDFs of papers into it. But the page rendering was so slow it was painful, and a real problem in class itself, since finding a particular passage would simply take too long.
More recently, I've acquired a Samsung Galaxy Tab 10.1, which makes for an excellent e-reader. It has a nice, bright screen, good resolution (1280x800), and lots of memory. Plus, I can access my course web site, or JSTOR, or whatever, directly from it (and with tools like AndFTP, I can even access my servers using SFTP and public key authentication).
But as I've mentioned elsewhere, a lot of the material I've scanned for my own use is in DjVu format, so I recently found myself needing to find a DjVu reader for Android.
It turns out (unsurprisingly, really) that there are several options, but the one on which I've settled for now is EBookDroid, a free and open source (GPL'd) ereader. Not only does it handle DjVu, it's got a lot of other nice features, such as the ability to set lots of named bookmarks (making particular passages easy to find). But one of the nicest things about it is that it will automatically split pages, if the file you are reading happens to have facing pages on a single page, like a photocopy. And it will automatically scale pages to the content area, not to mention wash your laundry and make your dinner. An excellent tool.
I've seen some people mention that EBookDroid "hijacks" PDF links from the browser, but I have not seen this issue myself. It does register itself as one possible PDF reader, but that is all.