Right now I have just coral and inverts as well, and I have had comments that I don't really need fish because the tank is so fascinating without them. I really like running it without fish, because it's filled with pods just running around and playing like little monkeys -- big ones will run at the little ones, which then scatter, for instance.
Lately I have had mysis really starting to get going, and those things are really neat the way they constantly glide around in figure-eights.
I see new stuff every day -- lots of times it's a new critter that I am trying to ID. As long as you have lps and softies, as Dakota9 says, you'll be fine.