I'm not sure how many ebooks I've read, but I know at least 12 and probably more than 20.
I really enjoyed reading ebooks on my palm IIIx and my palm zire 71 both now broken
Well, actually the zire still works but has this weird manufacturing flaw that stops the screen working (the touch screen comes away from the contacts and you need to squeeze the frame to get it to work).
I really liked ebooks because I could read them anywhere, and I was also in the military which meant I could easily bring several books with me on one deployment (training exercises, I never deployed to combat). Additionally, I was often sharing sleeping quarters, and with the ebooks I could read at night without bothering anyone else.
My preferred formats for all the stuff I read is as follows...
Fiction - Palm sized ebook reader
Reference (regulations, laws etc.) - Workstation
Manual (progamming, other technical things) - Paper