Smashwords is an online bookstore with thousands of e-books for sale, available in all the major E-Reader formats, as well as some of the minor formats. In fact, if you don't have an E-Reader yet, you can download a PDF to your computer, or just read your purchase on the site.
Mark Coker, who started Smashwords, has a great thing going IMO and is also a pleasant guy to deal with.
From March 6-12, there is a promotion going on at Smashwords, with a lot of titles half-off, 3/4s off, or even free. I'm participating, so you can get Virtual Pulp there for about $1.50 or Hell & Gone for $2.00. If you like to read, you should really visit and search for books in the genres that interest you. I'd definitely read the blurb and sample first before buying, though--it often gives you a clue as to how well the book is written.