I would go against the traditional monster set-ups you have, and do a wide array of peaceful SA Cichlids..
Such as.. Thorichthys, Festivums, Scalare, Aequidens, Geophagus.. But at the same time allow enough driftwood coverage for smaller species such as Crenicara, Apistogramma, Cupid Cichlids (anything lesser known..)..
THEN, I would add a large school of Dither fish for color and movement, perhaps like 60-100 rummynose or bleeding heart tetras. If they are too small, could do some of the rarer, larger species of tetras.. To keep your eyes trained towards the top, a large school of marble hatchets..
To compliment the bottom part of the tank do a large(24) school of Brochis, Corydoras, or find some of those rarer species like the Leptodoras, Semiaquidus, and Pterodoras..
Then to top it off, compliment them all with a variety of single oddballs.. such as a large Black or Brown Ghost Knife (mayber a rarer species?).. An Agenioesus catfish, some Tatia sp., and of course, a variety of Fancy Plecos.
I have been wanting to do a set-up like this.. Only based on the fact that YOU NEVER SEE IT.. Especially in large tanks.. Of course, all of the fish I listed above people usually keep in small species tanks. To see them in a large diverse biotope would be amazing. Most people who have large tanks like that always do the same ole' thing.. Rays, Dats, Aros.. Blah Blah Blah.. I would love to see a change of pace

Keep it in mind!