Re: Partition table messed up - hundreds of "ghost" partitions
I am not knowledgeable enough to discern much from the fsck for sda8. Inode 7 is toast and there are free block count mismatches. Obviously, don't try to fix it while it is mounted.
You could make a new 40GB partition on the new drive and copy the contents of sda8 to it before you repair it.
sudo rsync -vax /dev/sda8 /dev/sdbX
I'd probably just repair it.
When all this is working well enough, for absolute certainty, I would suggest you boot a live CD/USB and reformat the new drive, then manually create partitions on it into which you can copy the contents of the old partitions. This way you end up with perfect file systems. Then adjust the UUIDs in fstab files and reinstall Grub. Then you can dd clone the new drive back to the 500GB one. This will take a lot of time and I don't know whether this is strictly necessary.
I recommend rsync -ax --progress for copying partition contents
ASRock P67 Extreme6, Intel i5 2500K, 8GB RAM, nVidia 6600GT, 4x1TB RAID1+0