Don't forget to take a look at the PlantFinder. You should find it very useful. You should also find a lot of plants for sale from members that you probably can't find at your local fish store (aka LFS).
man i wish i had found this site a month and a half ago when i was looking for the plants to put in my 10gal cause i am using all SA plants in it and it was a PITA finding plants that originated form SA and were also small enough to fit in a 10gal
and i have a pretty good LFS but they arent that knowledgeable on plants but they are more than willing to order plants for me from their supplier which is what i did for the 10gal tank it has been a little difficult cause their supplier hasnt been cooperating with them but they have been helping me out whenever i go there