I have been meaning to post this for sometime now but for some odd reason it has remained in my drafts folder. I picked up a Seagate 1tb FreeAgent USB Drive for my AppleTV around 6 months ago. I tried to format it to HFS and it kept giving me errors. After searching for a few I found the fix for this.
Open Disk Utility
Click on the Partition
Click on the Current Volume Scheme drop-down and select One Partition
Click on the options button and chose either the GUID Partition button or the Apple Partition Map button
Click OK, you can adjust the other options if you so desire
Click Apply, The partition screen should open
After that has completed it will unmount and remount. Upon remount Time Machine might ask you about using the drive for backups, I chose no. Hope this helps anyone that has format issues with their Seagate 1tb FreeAgent.