Decalgirl skins are really great, a while ago i bought a solid yellow skin for my black DS,[a really botchy attempt to make it similar to the pikachu themed one]and its really durable. Very flexible too, and once you put it on it will stay on. The lamination doesnt peel, and is very durable in any sort of temperature.
However, once you remove the decal it will stretch the material, making it not fit your ds again. YES, it is re-appliable, NO, it won't fit your ds anymore.
(btw, i took mine off, solid black looked best for me. either that or a REAL pikachu edition.-.-)
However, the skin on my Wii is absoloutley fantastic. i suppose the skins look better on consoles without curves =/.