It's going to depend on what Mezz cards you have. Assuming you have a CNA like Qlogic or Emulex you only get 2 10GB ports per blade. Using one NIC solely for VMotion is kind of a waste unless your environment is very Vmotion heavy.
VMware is leaning folks towards using VLANs, and QOS to get beyond their old style of using lots of 1G NICs. You can take a look here http://blogs.vmware.com/networking/2010/05/vsphere-loves-10gige.html
So I would create one vSwitch with two NICs for redundancy and load balancing.You can use Nexus 1000V or VMware NetIOC for QOS.
If you are using the Cisco VIC (Palo) card you can create a VNIC and dedicate it to Vmotion with it's own QOS policy in UCSM
Also check out this link http://bradhedlund.com/ Brad has a lot of good information around UCS, VMware, and 10G
louis