I'm a fan of the
Roocase flip cases. They do a good job protecting the screen while the unit is in my bag, and I can slip out the inner "bikini" case for around the house. If you want to really protect the device, they also make a
zip portfolio version that uses the same "bikini" inside. Mind you, that thing is big!
I used the zip portfolio on my first tablets, but found them overly bulky in day-to-day use. I use the flip cases now.
Of course, I managed to drop my Galaxy Note when in the bikini whilst in the hospital, and it landed on a table leg in such a way that it took damage. If you want something really armored, you might want one of the
full-time bumper-type cases. I personally find they take away a lot of the enjoyment of having such a lightweight, svelte device.
Otterbox doesn't seem to have cases for the S series yet, but they're the tops in armor.