You don't need a bass specific synth to make basses. All synths have a pitch knob don't they? Just dial it down 24st and hit some keys.
If you only want to use presets, I can't help you, but if you want to be a real artist and design your own basses, I would say massive or synthmaster, possibly coupled with a distortion plugin.
For really epic basses, there's often a lot of processing post synth, so dust off your stock eqs, distortion, compression and chorus.