Aquasketch
This is my attempt to visualize my current scape with the excellent program Aquascetch.
http://www.theaquatools.com/content/view-your-sketch&num=10084
The program / site can be found here
http://www.theaquatools.com/aquasketcher
More information about it could be found here
http://www.aquaticplantcentral.com/forumapc/aquascaping/42807-aquasketch.html