I am probably the only person around here that had no problem at all with the Golem Twins ><;
Party- Robo, Aya, Crono.
Start off the battle with Robo and Aya's Boogie Double Tech. This ALWAYS stopped both of them my 9 or so times through the game ><; Then, when they are asleep, assign Robo Healer Duty with his Cure-All ability (The name escapes me right now). Then use Crono's and Aya's Falcon Hit. Over. And Over. And Over. And Over. Boogie when you need to, and just spam Falcon Hit.
Such an easy boss.
I think the hardest boss I ever had to deal with would be...
(Spoilers)
The Captain Blue robot fight on Ultra-V mode in Viewtiful Joe. The guy was a pain in the butt on Kids mode. On Normal, he was aggrivating. On V-Mode, he was very challenging, and on Ultra-V.... ARGH!!