I bought a Kobo because it was available locally (Canadian), reads epubs and .pdf so I wasn't trapped into books from a single source, was cheaper than the others (I lucked into a $129 weekend), had an SD expansion slot and has books preloaded.
My reason for wanting an e-reader was primarily because I read continually (for work and pleasure) and seem to end up lugging books with me whenever I travel. I was also getting tired of the mountains of paperbacks at the house (even regular trips to the charities who want books doesn't make much of a dent). The past few years my book purchases have been over the internet (no large book stores here) and our magazine subscriptions have migrated to e-editions so e-books seemed like the next thing to try. With e-ink technology I was willing to give a portable reader a chance.
As an author I was curious too. All my publications are in print and I have always been reluctant to move into e-publishing opportunities and markets. Now that I have seen the forms (web vs email vs ereaders) I feel like I am better informed (it also gives me a great way to review works in progress without sacrificing trees or being stuck in front of a monitor).