GTD apps on OS X

There seem to be lots of to-do managers and Getting Things Done applications on OS X lately. iGTD, which may have the best name, or at least one that's very easy to remember, seems to get 2 or 3 updates a day this week. It's free, but so is Actiontastic, which is also now open source. I need one of these which will allow me to access my things to do from two computers. It sounds like Actiontastic will do that eventually, but not yet. Maybe I can store the info on a thumb drive for now and do it that way.