Hiding the Taskbar Label Only for Specific Applications

The state of the taskbar, whether "Icons only", "Icons when full", or "Icon+label", is internally called the "glom" level, and is dictated by the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\TaskbarGlomLevel where the possible values are 0, 1, and 2 respectively. Unfortunately this is a taskbar-wide setting and there is no finer grain control to do what you want, which would be to make an icon-ified application wider to display title text, or an icon+text taskbar button smaller to hide the title text.

"Not exactly what you're looking for, but 7stacks from Alastria Software can put shortcuts for several applications in 1 taskbar icon, using ""stacks"" (à la Mac OS X).

7stacks is an easy to use, free app
that lets Windows 7 (and Vista and XP)
users have ""stacks"" of icons in their
Taskbar (in 7) or QuickLaunch Toolbar
(in Vista and XP). By using stacks,
users can reduce icon clutter, and
combine a group of related icons into
a single icon. For instance, if you
use application suites such as
Microsoft Office, OpenOffice, or Adobe
CS4, you can have all the suite's
icons combined into one icon!

I don't have access to my Windows 7 box now but you could try to specify an empty name for a new stack, use a custom icon and pin it to the taskbar."

"As AlucinariOlim said this program http://rammichael.com/7-taskbar-tweaker will do what you want.

I thought I'd just put in the instructions.

After installing taskbar tweaker open all the programs that you want to have a different label setting from your default.
Then open taskbar tweaker and click on the 'Taskbar Inspector' button.

A window will popup listing all the programs currently on the taskbar. Find the program that you want and right click on the row above it that has the arrow symbol next to it. I've shown an example in the image below.

Then in the menu that pops up hover on the 'show labels' option and then choose 'never' or 'always' according to your preference."