The vCenter server will be in the state it was when it was backed up. That may or may not be good for you. If these are the only VMs and you're using a single ESXi host, you may be in a good spot. The vCenter database (assuming you store the database on the vCenter Server) holds some alarm and event information, HA and DRS info, some host information, and historical performance data. You're likely not needing all this information back. It's likely much easier to just rebuild the vCenter server and restore the other VMs.
In the future, you may find that simply backing up the database is sufficient. In the event of a disaster, reinstall vCenter cleanly and then restore the database.
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Please consider marking this answer "correct" or "helpful" if you found it useful.
Mike Brown
VMware, Cisco Data Center, and NetApp dude
Consulting Engineer
michael.b.brown3@gmail.com
Twitter: @VirtuallyMikeB
Blog: http://VirtuallyMikeBrown.com
LinkedIn: http://LinkedIn.com/in/michaelbbrown
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Please consider marking this answer "correct" or "helpful" if you found it useful (you'll get points too).
Mike Brown
VMware, Cisco Data Center, and NetApp dude
Sr. Systems Engineer
michael.b.brown3@gmail.com
Twitter: @VirtuallyMikeB
Blog: http://VirtuallyMikeBrown.com
LinkedIn: http://LinkedIn.com/in/michaelbbrown