Hi, I'm Lowell from Eclypsia & Super Squad! Here is one of my most used builds, the Venom Share one.
You can find more details about the build here: http://www.guildwars2guru.com/topic/45902-lowells-ultimate-spvp-thief-guide-wip/
The core is 20 0 30 0 0, the last 20 points are up to you. I detail the possible choices in my guide.
To see this build in action, you can follow me here: http://www.own3d.tv/GW2Lowell/