I've just tried upgrading emacs from 21.3 to 22.2 on a Windows XP PC. Now my status bar and any source code appear blurry. (This wasn't the case in 21.3) It appears to be anything that uses Courier New. The Emacs splash screen (using Arial/graphics) is perfectly crisp.
I'm able to get crisp fonts again by setting w32-use-w32-font-dialog to nil, then changing the font through the menu options->Set Font/Fontset->Courier->Courier 12x9, but this makes all the text large.
I've installed emacs 22.2 in the same location as 21.3 was, but I've removed and replaced the entire emacs directory.