Honestly, as the others have said, I don't think they really make that big of an impact one way or another at this point. Sure if in the future e-books become the primary media then maybe it would be a different story. I'd assume this would also lead to paper books being printed on an on-demand structure since they wouldn't need large stockpiles of books to be distributed through brick and mortar stores.

Thats all speculation though.

One good thing though is that if you usually buy hardback novels, or even trade paperbacks, then you'll probably be able to save a few dollars on each purchase as most e-books run cheaper. Eventually you'd re-coup the cost of the e-reader and any saved funds could be contributed to a tree planting charity like arbor day or something similar.

Just an idea :-)

P.S. Green concernse aside I've loved my kindle. Being in a rural area I've had instant access to all the books I'd normally have to mail order and in the last two months I've read more books then I have in the last 3 years!