Never a dull moment, or even a lull, when it comes to Apple upgrade news. On the heels of last week's announcements about the company's new MacBook lineup, there's now buzz about new iMacs that could be out in time for the holidays. Apple Insider kicked off the latest round of speculation with a report Friday that Apple is expected to refresh its 20- and 24-inch iMacs "in the coming weeks," entering the shopping season with "one of its strongest product portfolios ever."