How large a tank, and how many oscars, what size?
I don't have an O presently but I tend to use the same methods for aquascaping my other large cichlid tanks. Based on a 75gal and a single fish, I usually have a 6" clay pot with the bottom broken out (grind the sharp edges!), a hunk of driftwood, and a couple weighted plastic or silk plants they can drag around, a couple of smooth fist sized rocks and a layer of gravel. As the fish grows, I remove the wood.
With a large fish, and depending on the fish's personality (if it is skittish or not), they need a lot of free space to move around. A 12" O freaking out in a 75gal with a couple big pieces of driftwood is a recipie for disaster.
The tank may look sparse, but its safe, and the O is the center of attention anyway...
If the tank is much larger, that would give you more options on aquascaping.
Burt