It should be noted that this is why a good to-do-list MANAGER is such a huge win -- and is a large part of what originally sold some folks on paper organizers and then sold many of us on PDAs such as the Palm. written properly, the program gives you ways of prioritizing the list such that you only see the top few (top seven?) items as judged by some combination of importance (a priority number) and urgency (a due date). If it isn't in that set, you don't worry about it yet, and the problem is solved.
Every now and then, when you AREN'T trying to Get Things Done, you take a bit of time to recheck your priorities and due dates. Or you may want to filter things by additional facts -- "I'm in the basement, what else needs to be done down here?" -- but still see only the top items from that filtered set.
Palm, and Research In Motion, got to-do lists and calendars right -- which is [a large part of] why those two platforms were the ones adopted by business types. [RIM also took security much more seriously than most of their competitors, which was a big sales advantage when you have to worry about industrial espionage.]
Friends who have used the Palm apps report that they have been completely unable to find anything on the iPhone/iTouch/iPad that comes close to the Palm's fit of tools to tasks, despite years of looking at alternatives. (Which is the single strongest reason I've never been very tempted by Apple's offerings in portable devices.) I don't know whether better alternatives exist for Android.
I'm not trying to claim that the Palm is better across the board than the newer devices. I just wish that they had put the kind of design time into functionality that Palm did, rather than letting making it pretty consume the entire budget. Or even that they'd just learned from Palm's experience. I'm sorry, but while that's a very pretty buggy wheel, nicely carved and painted and beautifully built out of the finest materials, it would be better if you'd noticed that someone else has already invented pneumatic tires.