Cisco WAN :: 2811 / Metro Ethernet Design Considerations?

I am planning on implementing a metro ethernet circuit to replace a more expensive circuit to connect my office and data center.  This circuit will be configured  by the provider in a 'transparent' manner, which will allow us to pass vlans freely over the circuit without having to create a QinQ tunnel.  This is a layer 2 only metro ethernet circuit.Planning on connecting the office end to a 3750 (switch A) and the data center end to a 2960 (switch B).  The data center end will have a couple of other 2960s hanging off of it for server connectivity (switches C & D). I plan to use a 2811 (router A)for layer 3 connectivity in the data center.  Switch B will plug into router A and switches C & D will plug into switch B using two port-channelled links.  I can post a diagram if needed.I will use rpvst here and configure switch B as the root bridge.There are about 10 vlans that I use between the office and data center.  Router A is also used to connect to other environments such as staging, production and also to the internet.   I think this should be a straight-forward configuration since it is mostly layer 2. Should switch B be the root bridge?