Anacharis grows really well, needs only a little light, and sucks up ammonia. I'd get it. =] You can anchor it down in the gravel or leave it floating. Trust me the look of it will grow on you. ;] And you can get TONS of it for super cheap.
Java moss and Java fern are nice too.
if you're looking for a list of plants and their care requirements I suggest this thread
. ;] You'll find what you need there. =]
For medium to high light plants (and low light plants will grow faster/benefit from this too) you'll want a Daylight (6,500 K(elvins)) Compact Fluorescent (CFL) bulb.
Since your tank is 5 gallons you'll want a bulb that's near 10 watts. I have a pair of 13 watts that I use for my 5 gallon (first bulb); and my 2 gallon, my quart, and my temp 1 gallon (second bulb).
They look like this:
They should fit into your light socket where the light that came with your tank is. =]