If you're trying to track all the tasks, I'd recommend using AgileZen, Pivotal Tracker or Trello.
AgileZen/Trello are both 'cardwall' implementations. I've not used Trello yet, but it looks like it's a bit slicker than Agile Zen.
AgileZen is much closer to a true kanban implementation; allowing work in progress limits, blocks, and ready to pull state. However it doesn't allow me to put rules of engagement on the board in an easy way.
Because you can expand the size of the board horizontally as far as you want, AgileZen/Trello are both good choices when work has a lot of hand offs (say your designer needs to do some work, then hand it to the executive, who rubber stamps it who hands it to the tech lead who designs it who gives it to the developers who code it who give it to QA who confirm it who give it to ops to deploy it)
Obviously that scenario is sub optimal. Thankfully kanban systems allow you to track how long cards stay stuck in different parts of the work flow. Now instead of wondering why it takes 3 weeks to get something from design to production, you can see where tasks are getting stuck! Hooray!
Pivotal Tracker is great if you are already running super lean. If you take a task and deploy it within a few hours to a day, then you should just use pivotal tracker. It's super smooth and clean.