[yapkuen]

The Precision Zen theme (the stock theme that ships with the Storm) has icons that consist of two layered images: the icon itself (which is transparent) and an overlay, which has the gradient effect near the top of the icon. A lot of user-made themes, such as the ones you would find in the themes forum here or in the CrackBerry store, use the icon without the overlay, resulting in a transparent icon.

[Snarfler]

The Precision Zen theme (the stock theme that ships with the Storm) has icons that consist of two layered images: the icon itself (which is transparent) and an overlay, which has the gradient effect near the top of the icon. A lot of user-made themes, such as the ones you would find in the themes forum here or in the CrackBerry store, use the icon without the overlay, resulting in a transparent icon.

I have tried some of the themes with truly transparent backgrounds on the icons, and they are ok, but it does make the choice of background image more important. SOme of the backgrounds I like made it harder to identify the icons, so I'm now running one of the hidden today themes with not so transparent icons.

But it is something you can choose by loading a theme that provides that.
And it is not really something I would use as a criteria on deciding whether or not to get a Storm.