My plan with this tank is to do a sort of "Nature Aquarium Biotope", where the layout mimics the scene of a Malaysian stream with dense vegetation on either side, lots of fallen trees, etc., and the flora and fauna are also from that biotope. I'm going to stretch the biotope concept a bit, because it will focus on the habitat of the fish I'm keeping - Pearl Gouramis, Harlequin Rasboras, and Siamese Algae Eaters. Even keeping those three together is a little bit of a stretch, but I'm going with it!
So the plant selection will be from habitats in which you would find these fish - streams and pools in Malaysia, Thailand, Sumatra, Java, etc. The main components will be crypt balansae, Java fern, java moss, hygrophila difformis, cyperus helferi, and a selection of other crypts: pontederiifolia, moehlmannii, affinis, albida, and I think one other I can't remember right now.
I plan on doing the planting this weekend, but I would appreciate any feedback you have on the hardscape. The small stones will be wrapped with java moss and be used to outline the stream. I don't plan on using cosmetic sand for the stream, I'm just going to keep the substrate clear of plants. So it should look like a black water stream. Black water, get it?

I plan on a big stand of c. balansae in the back left corner, with the H. difformis to the right of that, at the left focal point (in front of the filter, but behind the driftwood, and sloping down towards the stream edge). The sawn edge of that driftwood will be wrapped in a little moss, and I'll probably attach some Java fern to that piece. Then an assortment of crypts fill out the remainder of the left side midground and foreground.
On the right, I'll use mostly java fern attached to, and placed around, the "tree stump" (which is actually three pieces of malaysian driftwood that fit together almost perfectly to create that stump - I was soooo geeked when I pulled that off!). I want to use the c. helferi over here, too, but I'm not sure if it should be behind the stump on the right, or slightly to the left, near the stream edge. I'll use a few small crypts to fill out the right side foreground.
I'm not sure H. Difformis is quite the right plant for the left focal point - in my 20 long, it's just not growing tall and bushy the way I expected it too (I'll have a separate post on this later). I wanted something that would be a nice color and texture contrast to the darker greens of the crypts and ferns, and I thought h. difformis fit the bill nicely. I was looking through the APC Plant Finder (which is awesome, BTW - Thanks, Cavan!), and there were a couple of focal point-type plants from southeast Asia that caught my eye - rotala wallichi, rotala nanjenshan, hygro corymbosa 'stricta', h. corymbosa 'siamensis', barclaya longifolia, and hygrophila sp. "Red". Any thoughts or opinions? Note that this tank will not have CO2, and is probably a "moderate light" tank - I have four 40 watt T-12 bulbs with lousy reflectors.
I've also considered using downoi as a foreground plant, but in a moderate light, no CO2 tank, I'm not sure it will thrive.
Any and all feedback and opinions are appreciated - this is my first real attempt at an aquascape, where I didn't just stick plants where they would fit.