As you may know you can change the UI theme in Pharo.
Just click "System" - "Settings" to open the settings browser and select the user interface in the appearance section.
Beside the "Pharo" theme there are also themes called "Vistary" (if you like Windows) or "Watery"/"Watery2" (if you are used to Mac).
You can even implement own themes (as Doru demonstrates with his "White theme").
In the upcoming Pharo 3.0 you can even provide an own custom icon theme.Esteban demonstrates this with this goodie that allows Pharo to look like Eclipse since it uses the same icons as the Eclipse Java IDE.
Click on the screenshot images to zoom. Very useful if you want to show someone fluent in Java the wonderful world of Smalltalk.