okay well where to start......
Java fern is good anywhere. strap 10 young plantlets to a stick and in 6 months you'll have a totally relocatable java fern lollypop you can move every day of the week till your happy. (i have 4 of those!)
Java Moss - in high light tanks it MUST go in the shade. it's too slow growing and will get infested with algae if in strong direct light (it does in my tanks anyway).
For deeper tanks (ie 2ft deep low light tanks) where you want a carpeting plant to make a nice lawn etc... you can use java moss. look at my Pinned thread on Riccia, follow steps 8 and on. after about 4 weeks the java moss will have filled out. the new growth heads for the light hence giving the impression of hairgrass. keep the carpet to about 2 inches (haircut every 2 weeks or so) and hey presto a lush carpet in a low light tank.
Water Lillies (eg. Tiger Lotus) plant in between anubias species at least 10 inches from the tank walls as they need a lot of room to grow. when mature the lilly pads will shade the anubias helping to reduce spot algae on the leaves.
Glosso works rather well in shallow tanks as a low carpet, also works in deeper tanks but the carpet will be more of a cushion pad with some of the glosso growing upwards.
Vallis is rather useful to hide equipment (especially Juwel filter boxes - plant either side and they will hide it completely) and will make a nice background curtain
Anubias XXX are lovely plants, they attach firmly to rock or wood and bring the whole tank together. theres nothing worst than a bare lump of wood, big gap, big clump of stem plants, gap, bunch of blah blah....
personally i lay the wood and rocks in the tank first (before anything else), then add the substrate. fill the tank then plant. this way you are planting around the wood. sections are easier to identify and the whole job seems simpler. i remember the first time i planted a tank. bunch of plants in one hand and bare gravel in the tank, a bit daunting. with the wood in first you have something to build on.
for any bare areas that get lots of unshaded light - a riccia covered slate always looks the part.
well thats my twopence worth anyway, hope it helps someone