Do you find the default font in Windows Mail’s main window (see below — shown after resizing to 12 points) too tiny to read? What? You say the default 9 points isn’t big enough? It’s not big enough for me, either.
Fortunately, it’s not cast in stone. It’s controlled by Icon text size, accessible in Windows’ Appearance Settings.
To change it, right-click on Vista’s desktop and choose Personalize. In the Personalization settings, click on Window Color and Appearance. From there, click on the link to Open classic appearance properties for more color options. Then click on the Advanced button to display the Advanced Appearance dialog box, shown below.
Click the dropdown arrow next to Item, and choose Icon. Set the Font: Size: control to the desired font size, then click OK. Back in Appearance Settings, click either on OK or Apply (the latter if you think you might want to experiment a little before settling).
This setting will also make any text on the desktop itself larger, as well. Now, for me personally, that’s that a bad thing, but you might want to experiment with Item Size: if the larger text results in text being clipped on the desktop or in other place controlled by the Icon Font Size setting.