Although every software producer would ofcourse indicate their software as the perfect solution, there is really no one solution. Different needs require different software; some software is able to do more than other, but with flexibility comes complexity so the biggest solution is often not the right tool for the job. The problem seems subtly different for a lot of people searching for software to handle their situation.
The problem tackled by all project management software is dealing with the seemingly ever increasing flood of communicative requests, now that we are all connected to the internet. Keeping an overview of all things that are being worked on or should be done in the (near) future requires a bit of effort. It does help to clear your mind though, which helps to be more productive, so the organising effort is not wasted but rather an investment which should pay off.
A list of solutions follow:
Not much better than just using Notepad (which I actually have used more than Excel for planning tasks), a lot of people still use this program to do planning tasks. Excel is a spreadsheet though, and not really suited to keep track of your required actions after you've entered them. In that light, Notepad might be even better as it's easier to remove a line.
Conclusion: you can always do much better this, without a steep learning curve even.
Outlook has a list of tasks these days; the items are even categorizable. Still, it's a bit email-oriented; it seems to assume that all your tasks are somehow related to mail. This is not really the case my life, not sure about yours. It's more of an add-on to an email package, but not so much use when things get a bit more involved.
Conclusion: Outlook is nice for email, but not if you have a lot of things to do, and/or a lot of ideas.
A very complete package. It looks a bit like a spreadsheet, where you just type in tasks. Then you start subdividing tasks into subtasks. Quite suited for heavy projects.
If you look at the URL you can assume the color of the picture here. Still, I didn't make Organiser just for fun; MS Project was too complex and expensive, and I had my own ideas on my perfect organising tool. Also, liking the way Outlook handles multiple types of items, I added that to Organiser.
Here is my situation, things I find relevant to the way I want my planner/organiser to work:
That is really the focus of Organiser; to be able to deal with the above constraints fluently and quickly.
Conclusion: Organiser can go a long way if you fall into one of the categories above.
A web-based, social-media type approach to planning was created as a modern approach to project management. Here, read 'modern' as an alternative approach to project management; it's not necessarily better, but it might suit your situation better. Their focus is on communication; all messages go through BaseCamp and you can create groups to flow messages to the ones that ought to see it.
It therefore is more of a project communication tool, helping the project manager, rather than a tool to maintain a list of things that need to be done. You can check out the way they handle Todo items in this video (from their site). Although it looks nice, the project layout is a bit flat; you basically have groups of todo items, and that's as deep as it goes. Larger projects where you have over 30 things to do, will suffer from a single level of hierarchy.
It still is a completely different way than MS Project or Organiser, and if you're mostly into managing people, and not doing much of the actual work yourself, this might fit the bill.
Staction is really an alternative to BaseCamp. The focus is again on communication, rather than keeping an overview of things that need to be done. As projects grow, I'm afraid the same clutter will reappear, as it again focuses more on human interaction than a usable view of things that need to be done.
You can check out their product by clicking on the header above.
This site is also web-based and is more related to Organiser, although it's still quite different. The number of groups and subgroups you can create is quickly limited by the amount of space they take up onscreen. The same limitation applies that you really have 3 levels of hierarchy: groups, then projects, then tasks. For larger projects this will be a problem; for smaller projects it might be fine.