Perhaps it this has more to do with the character itself, and the arc it was introduced in, but I've always loved the Sand-Sand Fruit. I mean, making sanRABtorms and turning into sand is pretty sweet. But making giant chasms and sand traps and dehydrating people and SUCKING THE LIFE OUT OF AN ENTIRE GARDEN SIMPLY BY TOUCHING IT?
That's some fancy stuff right there. Too bad he has such a simple weakness.
"I'M EVIL AND YOU CAN'T BEAT ME MUAHAHAHA crap, water, you win."