Depending on your usage ~20GB should be enough for Windows - but you'll want to get it right because resizing an NTFS volume is a pain (with something like WinC

Depending on your usage ~20GB should be enough for Windows - but you'll want to get it right because resizing an NTFS volume is a pain (with something like WinClone). The second OS X partition, I don't think there aren't any DPs other than 10.6.5 that have been released to Mac Developer Program members (unless you're a Select or Premier?) and you can always install and use the included reversioner.... now 10.7 will be a different story when it comes along, but another ~10GB should be enough. I would put the rest of your disk to the main partition. You can startup the Mac from your boot DVD or find a Snow Leopard image and an external drive somewhere to use Disk Utility to repartition. edit: of course repartitioning will erase the drive, so backup carefully. edit2: actually, Disk Utility does have non-destructive partition editing but it hasn't worked the two times I've tried it, giving an error about unmovable files or something, but it might still be worth a try.