I like this mix:
All male Aulonacara (aka Peacocks)
Labs (any kind)
Cynotilapia (any kind)
Protomelas
Copadichromis
A single Juli
A single Compressiceps/Calvus
A single leluipi
A single daffodil
A single Tretocephalus
I'd stay away from Mbuna and big active haps like Venustus/Livingstoni mixed in with any of the above. IMHO, 75 gal really isn't big enough for a big hap tank but would suit a reasonable combo of the list above nicely. I'd keep any of the above out of an Mbuna tank.
My recommendation: either go overstocked all Mbuna (and a big hap here and there if you like) or for a more tranquil tank, any combo of the fish from above. Try to get all male Peacocks/Utaka with different colors to minimize aggression and avoid the breeding thing altogether (if you want). And either way you go, get really good filtration if you plan to overstock or even come close.