Hi all,
By default, Vista uses the black text color even under highlight in the toolbar/menubar, which isn't bad but it isn't consistent with the rest of Vista's menu's and isn't the best choice for optimum contrast and visibility.
This was something that bugged me and I had trouble finding it as I assumed it was in the 'Fonts, Colors, & System Metrics' section, but today I found it!
It is modifiable under "Toolbars, Headers and Rebar > Toolbars & Headers > Toolbar > <default>". Change the "HOT" and "PRESSED" TEXTCOLOR:COLOR property to white or your desired highlighted text color.
Here is the result (FYI, I modified the overlay color in the preview):