At first glance it appears you should use iBGP. This will give you the ability to advertise the same netblocks to both ISP's in a fault tolerant environment. If you use the same autonomous system number at both locations it will be iBGP. Of course you will need an underlying IGP to make this work properly.
Keep in mind you will need to have all iBGP speakers in a full mesh; if not a route-reflector should be used. Your topology is not complex enough to introduce confederations.