I think it's in IMAX 'till The Dark Knight is released. That's the only big IMAX release I can think of that would make theatres dump it. But - yeah - Speed Racer is going to be a cult classic.
Since I never saw Indiana Jones, this has been the most satisfying summer blockbuster season for me in ages (Iron Man, Speed Racer, The Incredible Hulk, Wall-E, Wanted) and I haven't seen The Dark Knight or Hellboy II, yet!