For a long plant, go with cyperus helferi. I literally got two decent sized plants for my WCMM tank this morning, and they look gorgeous spreading out from the corner, and works nice as a cover too. Totally my new favourite plant. Java fern and anubias are good, but I've found them both to be really slow growing. They do look nice though. My plants are all placed one side and make like a jungle area, with the rest of the tank open water for them to get their chase on.
I've never tried crypts, and I'm experimenting with an amazon sword at the moment. My other plants are stargrass, all three types of java fern, anubias, and a bundle of pennywort, which the minnows like pushing themselves in to.
Sorry for the ugly picture, my phone's camera is terrible.