I AM A BIG FAN of HoursTracker, an iOS app that is helping me burrow through important tasks.
In fact, the $2.99 app (also available for free) is doing more to positively affect my daily workflow than any other speed drills or GTD regimen. Part of the reason is how I carry the iPod Touch with me everywhere so I always have the app to hand. Every time I adjust the iPod's earbuds I think about what's on the HoursTracker schedule. I'm recording tasks as religiously as a time-motion study researcher because I'm bribing myself with a monthly pay-off based on what the app calculates as my billables. I'm also relating the app to my old skool Moleskine notes. The combination of the two of these practises improves my time-on-tasks by reducing my tendency to drift out of focus.
Check back in another month to see if HoursTracker is working as well for me when the heat of the academic term subsides.