I carry either the Speer 135gr Short Barrel +P ammo or the FBI Load in my M642 or M442. Both rounds work very well for me.
Like said above, you have to find a load YOU can shoot well from your revolver. The best ammo in the world will do you no good without good hits.
All the big name ammo companies have at least one .38 Special defensive round in their inventory and most are made with modern bullets that will do what they are supposed to do. Find one that you can shoot well.
Ammo I've carried in J frames:
Remington FBI Load #R38S12
Remington Golder Saber #GS38SB
Speer 135gr SB GDHP #23720
Federal FBI Load #38G
Federal 129gr Hydra-Shok #P38HS1
Federal 125gr Nyclad HP #P38MA
Winchester FBI Load #X38SPD
Winchester 125gr Silvertip #X38S8HP
DoubleTap 125gr Bonded JHP
HERE
All worked well in one revolver or another but not all worked well in all revolvers. IMO I would carry any of them as long as they were accurate in the revolver I was carrying.