An (extremely late) update:
I added some stem plants, guppies, and blue ramshorns. I've been having trouble with my CO2 and getting my ferts right, so algae has taken over. The water has cleared up, but I'm getting a lot of GSA. The guy that sold me the stem plants also sold me some light legs, so the tank now gets a much more even spread of light.
January 8th FTS:
Close up of the stems:
January 13th FTS:
Here's the lastest FTS (from January 28th, I think). I messed with this pic a bit to brighten it. With the algae and the frogbit, it's hard to get a decent exposure.
The guppies are two pairs of Japan blue doubleswords and a trio of delta Japan blues. Japan blue is a metallic color, so if the light isn't hitting them directly, they look mostly greyish with a tint of blue. The flash washes the color out a bit, but this is pretty much what they look like in real life:
The deltas are in the floating breeder trap.
The blue ramshorns look great, and they've bred, but the adults have been dying one by one every few days since I bought them. I'm down to my last two or three, so I'm considering putting them in a different tank.
I plan to do a lot of maintenance on this tank in the next week or so. It desperately needs fresh CO2 and a good scrub-down.