I wrote posts when we hit 1,000,000 files (Nov. 18, 2005) and 10,000 changesets (Sept. 26, 2005) on the DevDiv server. When you look at the April 2007 statistics (April 18, 2007) for that server, we're at 77,658,652 files and 204,556 changesets. Clearly, that's a huge change in roughly 18 months.
The file count climbs dramatically...