Actually, the part about re-installing isn't true, unless it is brand new with Tiger. I have an iBook and several Pismo (G-3) PowerBooks, and I installed Panther on them without having to resintall the original shipping OS first. I would expect the same with Tiger. You may want to check another source on this. In anycase, it is usually a mistake to play the waiting game because there is ALWAYS something new in the wings, just waiting a few months before being released.
Other than that you will be very, very pleased with your Mac. I've switched quite a few people and not one of them ever wants to go back to Windows.