I just got two cases I'm excited about - both Specks.
The SmartFlex Card can hold the phone and 3 cards or money Nice for when you're going out but don't want carry much but the phone. Surprisingly slim for a quasi-wallet/phone case. It holds the cards (whether one or three) snugly, but they're easy enough to push out using the cutout on the side. The only thing I'd change would be adding something to attach my car fob to. But I guess that would make it less sleek.
For when I don't need to carry cards, but still want the phone protected, I got the CandyShell Grip I really LOVE the tactile feel of this case! It's not bulky but the raised rubber strips add a nice no-slip feel to it. The buttons are covered too which I find makes them easier to use. And there's a nice bumper around the bezel area so if you lay your phone face down (or, it falls that way! ) there's some protection. I'm usually not a big fan of cases because I like the slim feel of the phone, but this one actually seems like an improvement, not a compromise to me.