Say it with me: "GTD is not a motivational system." It's great at helping you keep track of everything so you know where to find things and what you can do at a given place and time, but the urge to do those things has to come from somewhere else.

For some people, just having everything organized is energizing enough to get them to tear into their lists and get things done. For others, it can be tougher. For me, GTD finally highlighted my procrastination problems.

One of the challenges of starting GTD is learning to think of the actions without the baggage of the projects they move forward. It's one thing to see "Photoshop web header image" on a list and another thing to think about all the other web site development that still has to be done to get that project finished.

Another challenge is finding the right length for your lists. I discovered that I have a problem when I have to choose from too many options. Give me a list of 5 actions in a context, and I can crank through them. Give me a list of 15, and I can't make a choice. Do you have long lists?

You don't mention contexts. I presume you have chosen contexts and organized your actions accordingly -- but are those contexts really good reflections of your work?

Look at your action lists, and make sure that each action really truly is something you could do right now (or as soon as you find yourself in the appropriate context). Many items that end up on my action lists are really mini-projects or things that need something else done before I can get to them. That "something else" is really the next action, but that doesn't always leap to mind.

I agree with Paul -- set aside a block of time and just do. It may be forced and uncreative, but it can start the process of getting things knocked off your lists. GTD is a workflow management system, so your work needs to flow.

Give some of these things a try and let us know how it goes for you.