You can't have lost the bitcoins. If the transaction never gets committed, the 80 BTC never left. Your client just thinks they did. If the transaction does get committed, the 80 BTC will arrive at their destination.
Worst case, you can do the following:
1) Note the transaction ID.
2) Stop the client that sent the transaction.
3) Make sure the transaction is not in the block chain.
4) Make sure the transaction is not in the list of pending transactions. (Available here: http://bitcoincharts.com/bitcoin/
5) On the client you stopped, make a backup of the 'wallet.dat' file. Put it in one or more safe places.
6) db_dump the wallet.dat file to a text file.
7) Remove the wallet.dat file.
8 ) Search the text file for the *reversed* transaction ID. So if the txid start 1234567890..., search for 9078563412.
9) Remove the line starting with 02 and the following line, such that those two lines contain the transaction.
10) db_load the text file into the wallet.dat file.
11) Restart the client passing it the '-rescan' flag. The transaction should be gone.
12) Double-check the transaction is not in the block chain or list of pending transactions. If it is, stop your client and revert to the saved 'wallet.dat' file.
You're done. You're now in sync.
In the future, leave transaction fees at their defaults.
Alternatively, if you're in no hurry, just wait many hours with the client running. The coins will age and the transaction will gradually gain priority.
(The client really needs a way to delete an unconfirmed transaction.)