The Art Of The iOS Icon
One of those icons was designed for an app of mine :
http://itunes.apple.com/us/app/bill-organizer-manage-track/i...We (the designer and I) ultimately rejected it, because it just did not stand out at 57x57. 
As good as some of those icons look, you have to discipline yourself to view and evaluate them at 57x57, cos thats how the user is going to see them. Also bear in mind that the user will see them among a multitude of icons, so they have to stand out for more than just being pretty..I am tempted to conclude that these pretty icons just don't matter as much as we think they do, and the most effective ones may well be those with a solid bloc of color (like the path icon),  cos they are easier to make out on a crowded screen .