Logic goes 64 bit.
Apple just released Logic 9.1 via the software update process which is now can be run as a 64 bit application from inside Snow Leopard (Mac OSX 10.6). You can choose to run in 32 bit mode if you want, for compatibility with older soft synths and plugins. However, you can also run 32 bit plugins in 64 bit mode thanks to Logic's 32 bit Audio Unit Bridge, which launches automatically when you load songs using 32 bit plugins. This also allows you to start a song in 32 bit mode and once you have defined al the synths you want to use, then switch to 64 bit mode to take advantage of the faster processing. As a long term logic user I will only say--this is the best Logic yet!