I have found the Memory Manager default begins a vault1 for us. When this was explained to me I thought it would be a little confusing to have more than 1 vault at a time. You have all the folders you need and the timeline constantly keeps up with your dates.
I have found a good use for multiple vaults, though. I have made plans to begin a service of scanning pictures for other people. I would use an individual vault for each client and set up a shadow copy so that I had backup for them.
The answer to the question from Neilsongs is yes you can just begin importing into the default vault and I recommend not setting up multiple vaults for your personal photos.