Do you need a HOB configuration? If you have space under the tank I think a bucket canister would be more aesthetically pleasing.
At any rate, I think you will need considerably more than a 185 GPH pump by the time you get through the media. DC is the latest and greatest for aquaria and is a great choice if you're not pinching pennies. An advertised flow rate of 250-300 GPH would probably be more realistic by the time you add it to a system.