I have a development stack that I'm not willing to muddle with for days just to install an incremental OS update. My MBP was shipped with problems with Leopard. I expect those problems to be fixed. In Leopard.It is well past the time to upgrade to Snow Leopard. The other thing I might suggest is making sure you have the latest version of quicktime installed.
Dave
I have installed the update and will rent a full length movie from iTunes to test it. That was always where I would see hangs.