I own Ether, should I also own Ether Classic (are they one in the same)? If I own 100 Ether and believe in the technology behind it, and have owned them for 6 months or so, do I need to purchase Ether Classic as well to stand a chance to make some money down the road. Will Ether go away if Ether Classic succeeds, or are they one in the same?
If you had ETH before the hardfork, you now have both ETH and ETC. If you bought either ETH or ETC after the hardfork, you will only have that ETH or ETC.
The fork essentially created an alternate universe in which the stolen funds were magically transferred to a refund contract. It was believed by many that the original universe (i.e. the one without the transfer) would simply die as people stopped using it. This didn't happen, and now both universes continue exist.
Will either or both of them die? No one knows. At the moment, they are identical save for the transfer that did or not not happen. From a purely practical standpoint, dealing with both chains require additional precautions (basically, do not use the same address on both.) This may change in the future if either fork's community takes its own path.
(To add a few further details implied in a question that's a possible duplicate of this one... )
You'll need to have owned your ETH prior to the DAO-related hard fork, which happened on the following date (taken from this previous answer):
> new Date(eth.getBlock(1920000).timestamp * 1000).toUTCString() "Wed, 20 Jul 2016 13:20:40 UTC"
Any address/account owned prior to this will exist on both ETH and ETC chains.