I would say no to the oscars.. just a personal preference, and everyone has them.
I have a Jag, and a Midas together in the same tank, and the trouble maker is actually a 3" male convict! It can work out in some cases. The midas/jags are way more hyped up than they need to be.
For me, I would do a mix of large cichlids... probably SA/CA mix because these are my fish of choice.
I think that some Capintis would look really nice. They are colorful, and aren't as aggressive as the other large cichlids. I find these with parrot fish really give some good color contrast. I have this mix, as well as a honduran jag thrown in the mix and it makes for an interesting look at.
Frontosa would also be good if you wanted some color, but they don't have much personality, and are rather just something to look at and not interact with.
I think however that doing the typical pbass, bichir, tig routine would get old after awhile.
But in the end, it's really up to you, and the fish that you really want to have.