Same problem here in Windows XP pro. The message list fonts look identical to your screenshot. I've tried several things to change the default font in ZD, as well as trying to change the default windows system fonts, all to no avail.
I've browsed through bugzilla, and there two open bugs that look like they are actually both referring to this issue:
Bug
57943 anti aliasing, and
bug
37356 Allow user to select fonts.
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