An Exequror is a decent logistics cruiser, but if you want mining, use a Vexor - the ship has bonuses to mining drones, and is the best choice for a Gallente mining cruiser. Equip it with mining lasers in the turrets and mining drones, and light combat drones for defence against rats. Just be warned that unless you're willing to jet can mine, you'll have to shuttle back and forth between the belt and station a bit.
In terms of absolute efficiency, the Osprey is the way to go - best in terms of yield, carrying capacity and defense. It also doesn't take long to crosstrain into.
After that, its a question of where you want to go. If you're looking at pure/professional mining, then Alara is correct - Retriever/Covetor and then Hulk. But if not, you might want to look at refitting a battleship such as a Rokh, or in the Gallente case, Hyperion.
One last thing: Halada's Mining Guide
. This guide basically started my mining career, and I recommend it to anyone looking at mining.