That's assuming you have a Mac with that extra RAM. If you're running an iMac, MacBook Pro, or Mac Pro with 5GB RAM or less your machine (or in my case, my machine

) really doesn't have more RAM than can be accessed by a 32-bit application anyway
Orren,
I'm finding that I can access more memory on my 4GB iMac in 64-bit mode.
I was building an orchestral template using the Kirk Hunter Emerald library in Logic 9.02, but had to give up once Logic got to about 1.8 GB of real memory because of low memory warnings. With 9.1 in 64-bit mode, I completed the template and have so far got up to 2.3 GB of real memory without warnings. To check, I tried switching back to 32-bit mode, but got the plugins disabled message at about 1.8 GB of real memory.
Chris