Well, lionfish are actually pretty peaceful in that they don't chase fish, but what makes them suited in an aggressive tank is their poison and their huge stomach (and mouth, I've seen them gulf down a huge chunk of squid). I was really torn between an aggressive tank and a reef tank, but currently I'm set on an aggressive and hopefully down the road it might become a reef.
Lets say that you get a 100 gallon tank with like 100lbs lr. You could get a lot of cool corals, and suprisingly enough aggressive fish. Here's a list of fish that are technically and aggressive: All lions, most groupers (Panthers, Blue dot, Blue line, ect..), a few triggers (blue jaw, niger, pink tail), a few wrasses, and a most small eels. Also, hard corals are better choices for obvious reasons, but right now, I gotta go, I post more in a bit
-Mark