I've had the Otterbox defender on my iPad 1 since a week after getting it. Yeah it's a tank, but boy oh boy is it protected!
May go the same route, depending on how long it takes LifeProof to get their iPad case out.
My favorite is the Sena Ultraslim. It's a handmade leather pouch. I love it because when you use the iPad, it's bare and how it was meant to be used. When your not using it, all sides are protected. Little expensive at $60 but I have one for my iPad and iPhone. http://www.senacases.com/Apple/ipad-2-cases/ultraslim-cases/
I use the iMainGo XP as a case (it's also speakers and a stand too) and love it. I got hooked up with one from work and have been using it ever since. I travel a lot and it comes in handy for watching tv and movies (which I just downloaded the Time Warner app and it works great). Check it out here: http://amzn.to/iMainGoXP.
Now, to decide whether to get the new iPad or not...
Dodocase! Completely handmade and top notch quality! I had one for my iPad 2 and have just ordered one for my New iPad! I had a Classic, but they have some new ones for this latest release. http://www.dodocase.com/
I've always been a "thin as possible" sort of person when it comes to cases. But everything the for the iPad felt too flimsy to me. I really really like my Otterbox Defender, though. Not as bulky as you'd imagine, and the whole thing just feels solid. I can carry it around with confidence.
Have the Otterbox Defender and a Marware CEO Hybrid. Love them both. The Hybrid is very thin but offers good protection. I throw on the Defender if I'm going to be out in the field, but I tend to keep it in the Hybrid.
I have a defender on the way. I think the case will actually make the iPad easier to grasp with one hand, not to mention reduce the cursed finger marks everywhere!
Edit: How is the built in screen protector on it? Does it reduce the quality of the retina display like it does on the iPhone? On the phone I've knocked it out and just use a thin film type protector, wondering if I should order one for the iPad now.
I tried to like the built-in screen protector on the Defender. I think it's as good as those sorts of things get, but it still did odd things to the image quality. I eventually knocked mine out and put a crystal shield on. Perfect combo.