Well, to start with, you should be maintaining regular backups of the wallet in multiple secure locations. As long as you are doing that, you should be able to recover access to the bitcoins.
If for some reason you actually want the private key, you can use "dumpprivkey".
If you want a list of all the addresses in the wallet that have received bitcoins which haven't yet been spent, you can use "listunspent".
I'm following all suggestions but I still wanted the private key so I could add the wallet to my phones block chain app / account.
Thx.