Thanks a lot, my kindle is much less cluttered now I'd downloaded so many samples but I just don't bother with them - I work in a library now so tend to request/pick off shelves from there. I only really buy ebooks on the daily deal 99p thing.
I do have mine divided into fiction and non-fiction. Hadn't thought of putting books I've read into a separate folder though, might try that.
Yes you can share between lots of devices but greenhill is right, they must all be registered to the same amazon account. I have my kindle, my iPhone and DH's android phone all registered on mine - so if I get a book that I think DH will like, I go on kindlehome and under 'actions' select 'send to mrfuzzpig's android' and it costs no extra
If you have more than one person using the devices though it might be best to turn off Sync Between Devices.
You only pay once for a book, so if your Kindle breaks or you get another one or use your iPad to read from, you can download them from "the cloud". You can choose which device to send them to if you use your online Amazon account. This means you can also share books, presumably only on the same Amazon account name though, but I'm sure there'll be somebody along soon to help us do that too...
Yes, samples are deleted for ever, but if you removed a book from your Kindle device you can always get it back later. It is quite useful to set up a directory too, that way your home page doesn't get too cluttered. I put the books I've already read into one. You can do that by underlining the book and then click right when it's on the home page and scroll through the options.
Have you tried going to the home page on your Kindle, then selecting the sample by using the square arrow key? An arrow will appear on the underline pointing either to the left or right, click left and "delete" will appear under the line, click the centre of the square key and it should delete the sample. If you wanted to keep the sample or book, click right and then scroll through the options using the square arrow key.