i would recommend to do a dirt style substrate, very easy and low tech. you take organic soil, and cap it with small-medium sized gravel, never sand because the soil needs to breath.
once you do this then you are able to not worry about nutrients for the roots and with the right lighting the tank will take off.
for plant ideas you can do
dwarf hair grass and or dward sagittaria for the ground covering
green cobomba plant
assorted vallisneria plants, just with these you'll have to trip the tops if you want so that they grow straight up, because they will get to a length that will curve into the tank
java fern and anubias are great, but need something to hang onto like wood.
there are many other plants you can add, just some i listed.
now with planted tanks you need to think of the lighting.
for my 40 i have make shift 60W (energy saver kind) flouresent lights, which work great, have low light on my 20 and grows like crazy, then for my 40 which is medium- high light is growing great. needs work to allow the plants to grow in etc etc etc, but in the long run these lights are way cheaper then the fancy aquarium lights and do just the same
just they have a slight blue ting, and watching for algae is a must, but besides that it is great.
