Today I got the drive partitioned, formatted, XBMC and a couple of other tools installed. I used the excellent Auto-Installer Deluxe 4.5
DVD and the included XBpartitioner 1.1
I ended up creating the following partitions:
6 = 500.87GB, 32KB clusters
7 = 888.94GB, 64KB clusters
Note: It's best to keep the cluster sizes as low as possible because of wasted space. The last version of XBpartitioner enforces the correct cluster sizes so you don't have any data corruption issues.