I bought the Kindle Lighted Case, since I have a Kindle Keyboard that isn’t back lit. It plugs into my Kindle, and uses the Kindle battery for the light, so I don’t have to worry about charging it, or changing the batteries, plus it looks like a Moleskin notebook, so I can look cool and feel pretentious ! :D
If you have a Kindle Fire, you probably don’t care as much about having a light. There are soooo many really cute cases on both Amazon and places like etsy. I would recommend getting a hard case that folds over the front cover, rather than a sleeve cover or a soft cover, mainly because I think protects your Kindle better while traveling (I just throw mine into my purse, and I don’t have to worry about it getting banged around), and partly because it feels more like reading a book.
It also seems like a screen protector film might be good for a Kindle Fire, because I know I weep for days if I scratch my iPhone screen. As I said before though, I don’t have a touch screen Kindle, so I don’t know how much of a necessity that is.
I have a wall charger, but it must have come with my Kindle when I got it, because I don’t remember buying it separately.
Other than that, there isn’t really accessories I think you need. There are also tons of decals for all of the Kindles, but if you’re getting a case anyway, you may not want to plaster your Kindle with stickers (you probably won’t see them). If you load mp3s onto your Kindle or download Audible books, you might want to have a nice part of headphones.
Enjoy your Kindle!