i agree, like you went to the LFS and bought everything they had in three differet styles.
I prefer the grey rocks on the right, and the flat rocks, though i would go with a thinner slate insted of those thick ones. the round white ones should go. i like the driftwood, but it seems like those elements could be mixed together more smoothly instead of having separate sections for each. for example, when you do a rock pile, use layers of round rocks and layers of slate to make bigger caves and raise up the focal point, because everything is very low to the bottom. also, maybe you'd like to add some large hardy plants or plastic plants to increase the diversity of color and draw the eye upwards into the top half of the tank.