That is a great pic 214jay
ADW another snail you might like is a mystery snail. They get up to golfball size and come in a variety of colors.
Here is the nano list that someone was referring to earlier, if you havn't already found it:
http/www.fishforums.net/index.php?/topic/418749-nano-fish/ And if it was already linked, oops
Zebra danios..while they are small they are really active so most people would rather see them in a 4ft long tank.
They're also temperate (can someone tell me if this is the same thing as subtropical?) so can't be mixed with tropical fish due to temperature requirements.
As has been said, Celestial Pearl Danios are pretty small so you could have a good number. They are very beautiful, at least I think so.
A fish I'm not sure of if they have a requirement of how long a tank is but are small and pretty are Spotted Blue-eyes (pseudomugil gertrudae)
I'm also not sure if these are good for beginners or not, so hopefully someone else can say on that. I wanted to let them be known to you though
If you havn't already, you may want to go to your LFS and write down what fish look interesting to you and then come back here.