My friends and I are hardcore PC users for a long time. We didn't like Microsoft Windows Vista due to various reasons. For the time being, Microsoft Windows XP serves us well. Anyways, we will have to gradually shift to Vista and have to buy new computers as our office work requires it and as our old computers can't make the switch. Upgrading our old computers is not an option for us as we would end up replacing most of the components. We realized that Mac OS with iLife is great for our personal work where as Windows with our custom softwares is best suited for our office work. As Macs can run both operating systems very well, we decided to buy macs as our next computer and install both operating systems and required applications. As we are on the move with professional applications, we finalized on Macbook Pro laptops. The shift from Core Duo to Core 2 Duo was too fast that many of our colleagues felt that they burnt their hard earned money on Core Duo computers. We having been saving for our new computers from the last January and don't want to end up with an old technology. We decided to wait until June 2007, in order to get the next generation laptop with Mac OS X Leopard and iLife '07. With Leopard being delayed to October 2007, we are in a dilemma. We are hearing rumors that any new computers/upgrades will be released either with Leopard or after Leopard. With MacWorld in January 2008, does it make sense to make new purchases in June/October 2007? Fortunately, we can wait till January 2008. Our real question is if at all a new computer/upgrade is released in June/October 2007 what are the chances of them getting upgraded in January 2008? We don't want to experience the Core Duo to Core 2 Duo like scenarios. In short, should one buy after WWDC 2007 or after Macworld 2008?