Loismustdye: Ive got the STM skinny and the smart cover. Needless to say after 3 months use the STM skinny's "loop" to attach to the back for using as a stand now doesn't hold its shape and the case cannot be used as a stand anymore...... not impressed.
I can recommend the smart cover though, just make sure you get some sort of back protection like a skin or one of the cheap back covers on Trademe.
1eStar: I have used a marware microshell folio. Liked it a lot. Very thin and fine quality.
Now I have my own iPad I've ordered a cheap dealextreme case. Will probably order a marware off amazon if the dx one is too cheap and nasty.
adamroland: Otherwise, if your willing to spend the money, you can also get the Apple Smart Cover plus a clip on shell or softer rubberized case for the back of the iPad.