I think with 10k gallons you get the ability to collect multiples of some really large fish and really aggressive fish within the same environment.
For me I like the small fish. And all those lil critters that live in every nook and cranny of the rock work to me makes a good reef come alive. And in a tank of those proportions all the little gobies and blennies are lost to the expanse of water. You don't get close enough to even spot them.
The dream stock list for me is going to include groups of some fish - Yellow tangs, purple tangs, Hippo tangs, and then Highlight fish. While in a 10k gallon aquarium it might be amazing to watch 6 Achilles schooling together across the tank, I think the dynamic beauty of an Achilles might be lost in that situation. Groups of Zebrasommas and Hepatus, some worker tangs like Chevron, Flame tail - And then some show off tangs - Black, Gems, Malidives Powder Blue (look it up if you don't think there is a difference), an Achilles, a pair of mature blond Nasos.
Then adding to the mix of tangs would be an insane Angel collection - Personatus, Goldflake, Colini, Venustus, Harem of Flames, Joculator trio, interruptus harem, bellus harem, and a dozen more small pygmys.
And then comes what I call the doinker fish. These are the inexpensive fish that really fill out a reef aquarium, and in my opionion makes a reef tank a reef tank more than a fish tank with corals. Pseudochromis (by the dozens), Bar Gobies, FireFish Gobies (Schools of both), Cluster of Royal Grammas, Pair of Dejongi Grammas, Brilliant Black Cap Basslets, walls covered in assesors, barnacle blennies, red spotted blennies, all the varietes of mandarin gobies. Neon Gobies, Clown Gobies, Red Cap Gobies, Green Stripe Gobies, 100 eviota and trimma gobies. And Damsels - Lots and Lots and lots of selected Damsels - Starkii, Corazon, Springeri, Stegassi, Kupang, Talbots - All great community fish and not typical of the Damsel Stereo type.
And then the few oddities - Dragon Faced Pipefish, Blue stripe pipes and Janss pipefish. While I would love to be able to add the banded and multi-banded pipes to the list as well as some of the other less frequently seen pipes - I personally haven't been successful in keeping them long terms.
Dave B