ListView should allow adding and editing rows
@Pete, you're right.
But the problem of the DataGrid, and actually the entire fault of WPF compared to Silverlight, is that WPF is naked unlike Silverlight, just for an example, take a look at my SO question I posted long ago: http://stackoverflow.com/questions/1736530/wpf-datagrid-style-silverlight-datagrid, this is just an example but in fact, all Silverlight controls are styled much nicer than WPF (another example: RIA validation).
I would say since all the controls follow preset patterns and styles, there should be various themes out-the-box, that affects ALL the controls in the WPF system, and can be set in the application level, via code (with no need to copy xaml files to application, this is just another thought, it might also have few disadvantages as how a user can control these styles).
Have you considered using the DataGrid? If not, is there a reason why the DataGrid is inappropriate for this scenario?