Since alot of people are not aware that this exists and are only now interested in looking at such a thing with the BWE around the corner, I thought I'd post this.
http://gw2.luna-atra.fr/skills_tool/?lang=en
Gw2tools.com was also a good site for it, but seems to not be working atm.
Also worth checking out is the wiki:
http://wiki.guildwars2.com/wiki/Main_Page