I was very slow to jump on board, regularly spouting the purity of the actual book. I'm still a huge fan of actual books and will always prefer them - period.
That said; I got a tablet several months ago - not for reading, but for accessing the internet while traveling (great for dinner reservations, theater tickets, and online boarding passes). It had the Kindle app on it, so I gave it a test drive.
As an avid reader every night, after the Fam is tucked in and sawing logs, I thought it might be less intrusive than my book light. I have to say, it took a night or two to adjust, but I read for hours now before putting it away and going to sleep. No exaggeration, I read for maybe two or three hours every night - more than before. In fact, the last six books I read were all Kindle versions (three Star Wars, one fiction, and two non-fiction). Just started Allegiance two nights ago and I'm absolutely loving it (updates in the EU thread soon).
Still prefer an actual book, but very much a fan of Kindle. In the end, it's the story that's most important, not the medium. If I wake up in the middle of the night and can't fall asleep, I just grab it off the night stand and read some more. No more getting up and causing the dogs to stir, which thereby wakes my wife. I just quietly continue reading - and with much less light in the room.