Be careful with adding too much plants...the amount you put in the tank may look nice now, but as Bob said, some do grow really fast and can get out of control. There is a tank at my LFS where the LR is covered in plants and you can't see some of the corals...I was told that whenever they clean off the rock, it grows back within a couple of weeks so they just let it go.
A little dab of plants in the display will do ya...but I suggest keeping most of them in the sump/refugium. That way you get the benefits without the hassle of cleaning a lagoon.