Thanks for your input. That sounds like a sensible system too, so between all the comments I got, and the various options of Calibre and the reader, I have much food for thought and further experiments.

I intalled calibre, and it duplicated the entire 2 gb of my books on my hdd.

Yeah, that's one of my issues with whether to use Calibre or not. Seems you're either stuck with Calibre's folder system, or end up with duplicates...