Those of you who keep Rift Lake cichlids, especially mbuna from Malawi or any number of Tanganyikans, know that Texas holey rock are awesome rocks. In my opinion, you can never have enough, simply because each rock is unique and, together, they offer so many creative cave building possibilities.
Above is a photo of the 7 pieces I bought from my LFS today. Both of my current tanks contain a lot of this rock, which I believe, from a decorating flexibility perspective, provides the most options, especially if you're trying to maximize caves.
Everyone has their own preference for rock size, shape, etc. Personally, I like the smaller rocks because they 1) provide more stacking options, 2) they're easier to handle/clean, and 3) they're less likely to cause a major problem in the tank if they tumble.
The Cichlid Room Companion
Tropical Fish Hobbyist
American Cichlid Assoc.
African Cichlid Hub