The big element bike hubs/bottom brackets have to cope with is water and degreasers/solvents (excluding foreign debris like dirt/dust). No high pressure, no extreme heat, etc, like other bearings in the industrial world. Because of this, marine grease for marine trailer bearings will be the 'longest lasting' (at the expense of rolling resistance/wattage due to viscosity).

If you're looking for "cheap", you can buy Mystik JT-6 (MP) at your local Walmart for next to nothing...which is a favorite in marine world and out performs several big name brands on the data sheet.