A "good skin" is one that supports at least resolution of 480x320 (320x240 for WinCE). There are skins that does fancy things but failed to display 480x320 correctly. There are still lots of phones that uses 480x320 resolution, so don't just support resolutions higher than that. And I value stability and correctness over new functions. Doesn't do me any good if a skin have some fancy features and crashes sometimes.