[BigRedSpecial]

Looks like you've got a good starting point there. A few things I'd look out for though;

-as others said, the damsel will be aggressive towards most new fish

-be sure not to overstock - small marine tanks really can't handle many fish

-flow - depending on what corals you plan to keep, you may need more flow. What size is that maxijet? my 20g has two Aquaclear 70's, a Koralia 1 and a MJ900 and I still feel my flow is inadequate.

-You may want to place the GSP somewhere where it can't spread to other rocks... once the stuff takes off, it goes absolutely nuts. I've had GSP grow over(literally) Halimeda algae - not the fastest growing macro, but it should grow a hell of a lot faster than coral!