WOOT! I don't know what the problem was... I went to Time Machine Pref's turned Time Machine to Off, clicked change Backup Disk; selected the same disk and it works!

3/19/08 12:37:11 PM /System/Library/CoreServices/backupd[272] Backup requested by user
3/19/08 12:37:11 PM /System/Library/CoreServices/backupd[272] Starting standard backup
3/19/08 12:37:11 PM /System/Library/CoreServices/backupd[272] Backing up to: /Volumes/Backups/Backups.backupdb
3/19/08 12:37:11 PM /System/Library/CoreServices/backupd[272] Event store UUIDs don't match for volume: Hackintosh
3/19/08 12:37:15 PM /System/Library/CoreServices/backupd[272] Backup content size: 452.3 GB excluded items size: 436.1 GB for volume Hackintosh
3/19/08 12:37:15 PM /System/Library/CoreServices/backupd[272] No pre-backup thinning needed: 19.52 GB requested (including padding), 75.70 GB available