I really like my Crytocoryne aponogetifolia for a tall nice looking plant. They are not at all suitable for a short tank because the leaves get quite long. The plant in this picture that is curving across the top and back down the front of the tank is one of mine. It just reached the top of the tank when I got it but has grown a bit since under moderate light. In a low light tank I have one that is just up to the top and goes across the top a bit but has not gotten tall enough to curve back down like that.
The smaller large leaf plant that is more in the foreground is java fern. It needs to be tied to things like driftwood to keep its roots from getting buried and having the plant die. If positioned properly, it can cover a lot of things like filter tubes. It is also quite a nice plant under low to moderate light and is easier to find at the LFS.