Here's some more grist for the mill:
25,000 mile/1 year oil change intervals Even GM is admitting the 3,000 mile interval is passe. In 2004 their "April is Car Care Month" campaign advertised that the 3,000 mile oil change may be unnecessary.
As for me, I've switched to synthetic and am on the 10,000 mile/1 year change schedule. With my daily driver, if I used non-synthetic oil, I void the warranty
John