I don’t know if any of you were bothered by the fact that in Lion, the default icon size in Mail was much larger than it had been previously.
Personally it bugged the hell out of me, as I have a huge amount of mailboxes, and I didn’t know how to change the icon size.
Now I know. Go to System Preferences:General
And then chose Sidebar Icon size, which also controls the finder icon sidebar icon size (though not iTunes) and changes them within in Mail as well.
The default is medium, if you change it to small, the icons in mail are back to their old size.
Yes, so much more pleasing!