It appears that Google has quietly removed the file size figure from the search results. I am not sure when this happened, it could have been a year ago, but it did happen.
Now, the same search, does not return the file size:
A WebmasterWorld thread recently noticed this go missing from the search results. Most people are in favor of removing the file size label, being that many people have broadband connections these days. They rather see other information listed in the search results, such as if the site is in flash or if there is video or PDFs on the page, as opposed to the file size of a given web page.
Forum discussion at WebmasterWorld.