I see many are continuing to suggest one BHR (Big Honking Router (c)
@sfx2000) after another, all while perhaps forgetting these boxes pull much of their WAN-LAN numbers via offload schemes, which get disabled and send throughput right into the toilet as soon as one goes to do anything of consequence via CPU...
So if that's an issue, then x86, Tilera or similar architectures would be a better answer. Not sure if this fits the OP's use-case or skillset, but it will definitely get you the throughput your looking for with little to no weaknesses in terms of things you can/can't run on the box.
As long as we're pondering $200-300 BHRs, I figured it was at least worth a mention.