Depends on a size and type of a project. Considering most of support is needed for internal communication (within the team) not with the customer the most important features would be:

• task management (including tasks dependencies)
• scheduling
• bug tracking (it's interrelated with task management so using two different tools for these doesn't make much sense)
• history for each item
• at least basic reports
• import/export to MS Project (to make it easy importing plan at the beginning, end exporting in case the client needs mpp file)

The rest is optional:

• time tracking (usually it has to be integrated with accounting software so it's done somewhere else anyway)
• risk management (haven't seen it done properly yet)
• gantt chart (personally I can live without that)
• security (needed when you want to share item status with customers)

Marcus,

Not long ago, I wrote an article about the incompleteness of project management products in the sense that no single product has all the functionality needed by a PM. You can read it here: http://www.expiriance.com/blogs/pm/2009/08/pm-products-are-not-complete.php

I am also interested in the answers to your question.

Best regards.

My company makes a project management system (AceProject) and in my experience there are as many ways to use a PM software as there are project teams. The features people want depend on the level of maturity of project management in the organization, the type and size of projects managed, and corporate culture.

However, people are looking for these basic feature sets:

• A way to track tasks
• A way to track time
• A way to report on the above
• A way to share this information with others