if the light really is important (and it was for me, i like to read in bed) then the official amazon case with light is a great but expensive option. the light pushes in and out of the case, so is unobtrusive if you don't need it, plus it takes the power from the kindle itself, so you're not mucking around with separate leads or batteries or what have you. though, for all i know, there may be equally good alternatives.
