If you like Windows 7 new taskbar and want it something like that in your Kubuntu, consider yourself lucky. There's a Smooth Task, an Icon Only (or Windows 7 taskbar like ) widget for Plasma created by Mathias Panzenböck.
This taskbar also has window preview in thumbnail like Windows 7 when you use the kwin '"highlight window'"effect. I don't use kwin but compiz, but it can also display tooltip of window' titles in place of thumbnail preview.

smooth task in kubuntu, it goes well with seven theme

For more detail and download page go to kde-look.org It is available as a source file, meaning it's not a just-click-to-install kind of file, you have to compile it yourself. Don't worry though there's a ready-to-use .deb package, download it here.
After installation, you can add it via Add Widget menu, you can add it as a free widget on your desktop or have it docked in your bottom bar by click and drag into it, like mine (pictured above).

keyword : icon only, windows 7 like, taskbar, kubuntu