I first got into ebooks thanks to my trusty pocket PC in the form of a smartphone. I quickly realized the joy of being able to just read anywhere, anytime. Not just a single book, but a whole library crammed in a fingernail-sized memory card. Nothing can beat that. Besides, if I crave to read THIS ONE BOOK JUST NOW and it's not in my library, I can download it in a whim.
Now I've also got myself a 6" e-ink reader, for more screen real state and reading under day light. Shares same library than my smartphone, managed by Calibre on the laptop.