TXT format was OK as I could read in any text ap. My preference being Whiz of course. I would always copy/paste the text out of Notepad into a WhizFolder document which I could turn into a hyperlinked file with a table of contents and have plenty of space to make my own notes. But that was time consuming and I had to hunt down the metadata myself if I wanted it--bookcovers, author, title, publisher, tags, etc.
HTML limited me to reading online unless I wanted to copy/paste the text into Whiz. But HTML books were split up into chapters and thus there could be anywhere from 5 to 50 separate open-copy-paste-fix format issues tasks to get the whole book. I did this for the complete plays of Shakespeare and for Proust's Remembrance of Things Past and both took me hours. It was worth it as I enjoy reading and annotating ebooks in Whiz but the tedious chore that was had me hesitant to do it very often.
PDF is nice in many ways but it won't allow me to word wrap to a narrow column which is essential for me for faster reading as due to my lack of peripheral vision my eyes tend to get lost traversing back to the beginning of the next line when those lines are longer than five words.
One of the things I discovered the week I started reading in the Kindle for PC was the by enlarging the font and narrowing the line I could more than double my current reading speed with tree books of regular font for which my speed has fallen to 20 pages an hour at my peak before eyestrain drops it even further. On the very first day with the Kindle for PC I found myself reading forvan hour without noticing any eyestrain and when I checked how far I read I found it to be 25% of a 255 page book. Which works out to 63 pages.
It has been over 15 years since I averaged above 60 pages an hour. Ten years ago I was at 50. 20 years ago at 60 to 70. In highschool and through my early to mid 20s I pushed 100 pages an hour for most fiction. It has been very frustrating to loose the speed and the ability to read for long hours without eyestrain. Reading on the computer screen has given that back to me. That is probably why I found myself spending more and more time on the computer and reading news and blogs online.
So when I encountered a EPUB I couldn't get in other formats I decided it was time to figure out what I needed on my computer in order to read EPUB documents. A quick Google search brought me to Calibre.
Not only could it open EPUB documents in its viewer it could convert them to the Kindle format, PDF, HTML, and many others. And if that wasn't enough it can manage a large ebook library, sync with reader of your choice, and download news from around the world.
All of that and it is FREE!
Here's a few of my free ebook sources: