I logged in today at around 6pm and Windows Update greeted me with a pleasant surprise: the SP2 patch for Office 2007 is now available.
If Windows Update is not activated, you can alternately download the 292MB installer from here.
The full list of improvements and bug fixes from SP2 is listed in full details here, but the most significant of them was the native support for publishing the created document as PDF, XPS or ODF (open document format). In previous versions, you need to download and install a separate installer in order to save your document as a PDF or XPS file. Other improvements of note include new enhancements for SmartArt and increased performance for Outlook.