I second Hans, but if you'd like to try a package deal, I also order from Planted Aquariums Central. I bought her 20 gallon package recently and it was worth it.
If you don't like her package deals, you can certainly mix and match and create your own. She also does a point thing on her site where you get X amount of points per purchase. i.e- If you spend $5.00, you get 5 points. Points than can be applied to freebie plants once you'd collected enough which I think is pretty neat as I haven't seen any other plant site do that.