Yep, I have definitely tried a few, I'm a bit of a casophile. And it's a hard choice, many are beautiful, like the Dodo and the Bookbook and the Grove.
(These are not books, they are Bookbook cases!)
But those are not exactly cheap (Actually Amazon US is currently selling the Dodo for only $52, a good deal). One really good case is economical, though, the aCase iPad case. (Here's a UK link.) It's functionally one of the best I've tried, it's hard to believe they can sell it for sixteen dollars. It's faux leather, but looks good. It's not heavy and has different angles as a stand, so I've used it a lot.
I bought it for the iPad 1, but the iPad 2 fits perfectly also.
What's funny is that a much more expensive European case, the Jivo, is identical in design to the aCase. I mean totally, they are clearly made in the same machines. The only difference is that it's admittedly more beautiful, since it's made in real leather and a suede-like inside lining, and comes in different colors (I have a pretty red one). But the price difference! Eighty Euros, over 100 dollars. So the aCase is a great deal.
... Hmm, but here again, Amazon, this time UK, is selling it much cheaper (40 Pounds Sterling currently, about $60). I wonder if the hard times have hit the case market.