For multi-disc games though, I hope you won't have to go back to the dash, then browse over and select play from HDD. I hope the 360 will check to see if the next disc is in the HDD or not and simply have us put in the disc, or else actually run it from the disc if we don't have it installed.
*Edit* The Innocent X: I think all that's been officially said is that "HDD installs work great with multi-disc games". I'm not sure any details have been given about it at this point.