I switched over to ebooks completely a few years ago, with the exception of cookbooks and books on witchcraft - and some of those are becoming available as ebooks, so I anticipate migrating those collections in the next few years.
I used to have boxes upon boxes upon shelves of pbooks - at one point I had over 3000 books in my bedroom alone. Then I discovered ebooks through Baen's Webscriptions and Free Library in 2001.
I have never looked back.
I have had many different devices - my first device I read ebooks on was a Palm M105. This led to a M125, then an M515, then a Tapwave Zodiac, then a Palm Lifedrive, then a Palm TX, then an HTC Wizard, an HTC Kaiser, and my current combination of a Sony 505 and an iPod Touch.
I do not buy paper books anymore.
The last exception I made was Harry Potter book 7, which went into the yard sale bin as soon as I finished it the next day.
I love going into bookstores. The smell, the aura - all things I adore. But I don't buy anything other than coffee there, and I browse the shelves with a pad of paper to write down the books I like the looks of to look for as ebooks when I get home.
Ebooks do not develop broken spines and dogeared pages. They do not have questionable substances appear on the pages like many library books I have had the misfortune of borrowing. They do not lose pages, get ripped pages, get water damaged (although the reader can - but that is what backups are for).
All in all, they are a much preferred format (although I am the first to admit that there is no used ebook market, as no one has to make the choice between storage for old books vs. storage for new books. I do miss the hunt for an out of print pbook - I used to haunt used bookstores.)
There have been a few trade offs. But I regret nothing!
Mare