I installed Windows 7 Ultimate 64-bit edition on a 1TB drive in my Mac Pro today, and after installing the Boot Camp 3.0 drivers off the Snow Leopard disc, it was able to see my other hard drives with OS X file system partitions on them.
Only thing is, they didn't show up in Win 7 in the order I expected. (I have a drive called "Data 1" and another called "Data 2", but Windows 7 decided to assign the "Data 2" drive as letter F: and the "Data 1" as G
So, knowing how Windows is with its drive letters, I went to the Disk Management program under Administrative Tools, and reassigned the drive letters so they were in the order I wanted. Worked great, UNTIL I rebooted into OS X. That's when I discovered Windows 7 clobbered those partitions. OS X doesn't recognize the drives as having valid partitions on them anymore!
Only way I can see the data on them now is to boot back into Windows 7, where it happily views it all!
Tried running Disk Utility in OS X to fix the drives but it refused to even try, reporting I needed to try to back up any data possible and reformat!?!
This appears to just be a matter of Win 7 modifying an identifier of some sort in the directory table. Anyone know a way to fix this?