How do I put my music back on my laptop from my iPod touch after it crashed?
Did you fail to maintain a backup copy of your computer?
You can transfer itunes purchases from an ipod: File>Devices>Transfer Purchases
This user tip should be helpful. It refers to the iPhone, but it's equally valid for iPods as well…
Syncing to a "New" Computer or replacing a "crashed" Hard Drive
See also Recover your iTunes library from your iPod or iOS device.
Retrieving data ...