Sometimes it's the tiniest things that can bug you about a user interface like the colour of your taskbar changing as your wallpaper cycles. This simple but clever hack will keep your Aero transparency on but your taskbar colours consistent.
The absolute simplest way to keep your taskbar the same colour would be to disable transparency and set it to the colour you wanted. This unfortunately disables transparency across all windows, not just the taskbar. If you like transparent windows but you'd like a consistently coloured taskbar the solution is a dead simple but clever wallpaper hack. Over at the how-to site How-To Geek they elaborate:
The secret to changing the taskbar colour is to change the desktop wallpaper and add a coloured stripe at the bottom right in back of where the taskbar is. For this exercise, we're going to illustrate with the freeware Paint.Net application, but you could do the same with any image editor.
Before we begin, make absolutely certain that your wallpaper is the same dimensions as your desktop. This won't work very well otherwise.
The easiest way to put a stripe at the bottom of the image is to use the Canvas Size feature to chop off the bottom of the image, and then add it back.
I followed along with their tutorial and created the wallpaper test image seen in the screenshot above. The wallpaper itself is a brightly lit white scene but the toolbar, thanks to the black stripe I added at the bottom of the wallpaper, remains dark. I like the effect enough that I'm tempted to divide up all the wallpaper in my custom wallpaper directory between light and dark backgrounds and apply a black and white stripe, respectively, to them using a Photoshop batch script.
Check out the link below for a full walk-through tutorial complete with pictures. Have a clever wallpaper or GUI-related hack to share? Let's hear about it in the comments.