For those of you running Snow Leopard on newer Macs, you might be disapointed to know that you are probably running in 32-bit mode. I have a brand new MacBook Pro and am running 32-bit. I'd wager that some of you are too. The problem is that no matter what hardware you are running, Apple puts you into 32 bit mode (Except Xserves).
Would you like to see what it is like to run in the 64-Bit world? First make sure you have the right hardware for the job. Apple will only let you run 64-bit if you have a 64-bit firmware. Here's a list from the Snow Leopard release notes:
