Live plants are a great help with keeping water quality. They also release oxygen which is obviously good.
I personally use a lot of live plants in my tanks. I have no problems with growth, in fact they grow like crazy. I recently "cleaned" my 60l tank and i took out LOTS of Elodea...(a whole bucket xD)
AS you can imagine, Elodea works brilliantly, java moss and java fern grow well in shady conditions although they grow slowlier. Anubias is another type of plant that grows in the shade.
The only concern with live plants is that you need to clean the debriss that over time builds up in the bottom of the tank(which you have to do anyway.....)