Really any plants will do. I woudl pick ones you liek to look at. If you tank is on the low light side and you want something easy then I would suggest Java Fern. It is a broad leaved plant that requires very little help. Crypts are nice, though can be on the finicky side sometimes. A sword plant can look very nice and can work in a 10 gallon, it will just require pruning occasionally once it is established. It could be moved into the 55 gallon later though.
You can't beat water sprite. It grows quickly, and you can use it as a floating plant or root it in the gravel. It will provide hiding places for fry. Little plants spring up on the leaves. New plants will even start on broken-off pieces of leaf.
Crypts work well ina 10 gallon with plant substrate under variety of light conditions and depending on wether you inject Co2. (they love it from my experience but not required).