Before the latest Beta I've used 2165 with "draw_white_space": "all" enabled which was very handy for Markdown editing.
With 2181 (or is it 2180? anyway, the auto-updated one) I can hardly see the dots for spaces at all, since they are extremely faint and don't care for changes in the .tmTheme.
Before: http://cl.ly/0Z1M201J2d143T3i2z2v/Screen%20Shot%202012-02-23%20at%201.45.05%20PM.pngAfter: http://cl.ly/2c2k1h380P1c2w0Q002Q/Screen%20Shot%202012-02-23%20at%201.50.02%20PM.png
I'm having the same problem in ST2. Was it resolved ? Any way to change color of those "invisible" characters ?