I'm thinking of buying a Kindle, but would like to get some opinions first. Hopefully some folk here have by now been using their Kindles for quite a while. What are your long-term impressions? Do you actually use your Kindle as a total replacement for buying and reading books? Is it worth paying extra for 3G? Is that 6" screen big enough? How robust are they? Would you take your Kindle to the beach or pool-side? Is the lack of colour a drawback and should I wait until the version with a colour screen is on sale?