For starters there's native USB 3.0 (many 6-series boards provided it through a 3rd party controller) as well as guaranteed PCIe 3.0 support on the slots that branch off of the CPU.
MSI showed us two Z77 boards, the Z77A-GD80 and the Z77-GD65. The GD80 is unique because it will actually ship with Thunderbolt support.
The controller hasn't been placed on the board yet, nor has the Thunderbolt port, but the design is nearly complete.
MSI doesn't have an estimate on pricing yet but I'm hearing that the Thunderbolt controller should add another $20 - $30 on average to any design.
Gallery: MSI's Z77 Ivy Bridge Motherboards at CES, Now With Thunderbolt Support.