I had to upgrade one of my development computers to Snow Leopard to develop for iPad. It has a LOT of software installed on it. Snow Leopard CD in, installation runs, upgrade done, all apps working! Simple. 64 bit OS X. I'm now developing for 64 bit Windows using Windows 7, and 64 bit OS X using Snow Leopard.

64 bit doesn't sound like a big deal to the average user, but consider this..., I can now theoretically address 16 exabytes of RAM (not slow, disk swapped cache memory, but RAM). Aside from the cost of over 400 billion dollars, there is also some support hardware required that is not typically available in today's computers. Soon. But, you can now buy computers with 16 gigabytes of memory, gigabytes, and use it all. Can you imagine the games that you could design with that type of memory available?? Awesome.