For planetary, early interstellar precursor and simple omniplanetary applications, ACMF (antimatter catalyzed fusion) exhibits the best performance. The reference case of a 1-year human round-trip mission to Jupiter with a 10 to 100 metric ton (mT) payload requires an antimatter quantity of 1 to 10 micrograms (μg). It appears as though this requirement could drop into the 1 to 10 ng range for payloads consistent with unmanned, planetary missions.
So fuel for a trip to Jupiter (in one year!) every week.