Koreader supports Calibre wirelessly, so there's no need to ever mess with a USB cable again. It also has no telemetry, does not nag about unregistereded device and, doesn't force you to give up Wi‑Fi(there are quite a few websites designed for ereaders). It can read RSS, natively supports EPUB, and offers a custom dictionary, custom screensaver, custom status bar, and a better horizontal mode, including columns.

I've been avoding messing with my Kindle when I was doing the same thing; not registering and using Calibre. But the latest news gave me a reason to try and I regret not doing this earlier.

edit: Fixed name.