Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.
Weekly updates are probably the second most important part of GTD. Which makes it less than or equal to good that I suck so horribly at it. The hardest parts for me are probably A) getting around to it (kind of ironic, no?) and 2) taking too long to do it (although I may be wrong on that count).
The biggest part of my weekly review right now is maintaining a spreadsheet listing out all my current projects and the steps for each, in order. I then take the next step from each project and put it onto Remember the Milk. It seems to work well. It definitely helps keeping the spreadsheet because you really don't know all the steps for even a medium or small sized project until you sit down and list them out. One of the crucial things for Getting Things Done (or GTD) is that everything on the actual tasklist is something you can do. That was a big pitfall for me in the past. I would have something like "achieve world peace" on my tasklist. I'd take one look at it and go "ugh" and never get started on it. Or I would want to do it, but I'd sit and ponder for a while thinking what the next step toward that monster project would be and I'd either A) not remember, 2) think of the step 2 steps ahead or C) waste too much time figuring out something I'd figured out last week. The weekly review is Cyberdyne (and maybe an ad-hoc review here and there), but during the majority of the week, I am simply a task terminator.
Next I plan to play around with Mind Mapping, figure out why its better than using my whiteboard or Evernote and whether or not I really want to step up to THAT level of geekiness.
I'd like to take one final second to give a shout out to my favorite lunchtime web series, Man In the Box Show.