An Intel employee published a screenshot of the Windows Server 2008 R2 task manager on a system with a chip with 256 cores:
Sometime between now and when we're more likely to see machines with this level of parallelism it might be an appropriate area for some UI redesign. I don't know many IT administrators or developers that have a 30" LCD monitor, okay I know one and it isn't me unfortunately.
Windows 7 and Windows Server 2008 R2 group logical processors into sub groups and it would therefore make sense that the task manager be redesigned to show the performance of processors by group. Without which you'll definitely need a 30" LCD. That said however, if you can afford a 256 logical processor machine then you'll probably be able to find a few extra dollars for a large display.