hmmmm, that's actually quite a loaded question. A lot depends on how big your tank is, and more importantly, how much light you ahve. My advise would be log onto Plantgeek.com. They have a TON of info about live plants, and a forum just like this one. In fact, many of the people here are also there (right Isabella?? lol)
PlantGeek is loaded with info that you might find usefull. This is a question that doesnt have one line answer. Its more $$$ more work and more agrevation but at the end its worth it. I would never consider having fake plants in my tanks.I didnt have a tank since I was a kid and i just started one recently and thanx to everyone at PlantGeek it looks great. Check it out there is a link in my sig.