Part of the KOffice suite, KPlato is a comprehensive task management application. Not only does KPlato provide tools for task tracking and scheduling, but it also has the ability to track and analyze costs associated with these tasks. Using this feature, you can quantify how deviations from your set schedule affect the bottom line.
KPlato has a tool that can associate resources with tasks, along with costs. This enables the user to keep track of resource allocation throughout a project's duration. Throw in all the analytical tools, and KPlato can be a pretty effective piece of software for even larger scale and complex operations.
TaskJuggler is a custom, detail-oriented project manager. While there is a GUI, you have to enter your resources and tasks manually, Notepad-style. This is intimidating, but it grants you the ability to add declarations, attributes, flags, and macros for almost anything. Once it's all done, simply select the Report tab to see graphical charts showing pretty much whatever view you want, provided you entered the information properly into the Editor tab.
Setting up a project of any scope in TaskJuggler can be a major pain, but because of its manual editor, keeping track of almost every minute detail of a project is possible. TaskJuggler is probably worth the time for larger projects, due to its abilty to custom tailor reports on almost everything.
Planner is the project management part of the GNOME Office suite. Planner has four different tools or views for interacting with your project. They can be accessed by a slim left-hand pane and displayed on the rest of the screen.
The top view is Gantt view. This is a Gantt chart showing the smaller tasks that comprise your entire project, all in a time line view with the resources needed for each task shown attached to that task. The Tasks view allows for the creation and editing of individual tasks and the assigning of resources to tasks. The Resources view is for the creation and classification of resources. Finally, the ResourcesUsage view is a graphical representation of your resource usage, like the Gantt view, but emphasizing resources instead of tasks.
By associating costs with resources, both material and human, Planner lets you keep tabs on the total cost of a project. Planner has promise, but lacks the polish of KPlato and the sophistication of TaskJuggler.