Who's got an idea for this tank?

Hey guys! I convinced my dad, and sacrificed several things, to let me set up my bro's empty 50 gallon tank. It's gonna be planted, but there's only one problem... I don't know what plants to put in it! I know this is a grand opportunity to get some big/tall plants, so I think that I'll get some Vals, at least. I need some ideas for background and midground plants. Also, for the foreground, I was planning on a fast growing, relatively low growing plant (Relatively low growing, like Hydrocotyle Tripartitia) that has the majority of it's leaves a few inches above the substrate. The reason I want that affect is to have only dim light below the foreground plant so that the main fish, which I think is gonna be an African Brown Knife fish, to come out during the day, hiding under the HT (Abbreviation for Hydrocotyle Tripartitia) for cover, and so I can see him.

To narrow the list of possible set ups down a bit, his will be a medium-high light tank, medium-high meaning it's in between medium and high. The light is the Odyssea 36" T5-HO dual bulb fixture. I will not empty my pockets of cash for a CO2 system, so no really difficult plants please. I will be dosing the everyday Macro and Micronutrients, and I will have root tabs. To narrow down the possibilities further, the tank's dimensions are 36" long (Duh!), 20 inches high, and 15 inches wide.

So, start throwing ideas out there!!

THANK YOU SO MUCH!!!