One of the aspects of the current Windows Task Manager UI that doesn't scale particularly well, even on existing systems, is the CPU Usage monitor. Trying to track more than four cores quickly devolves into a game of "find the thread." The more cores you have, the less useful information the panel conveys. The 60s moving average CPU utilization line goes from a useful point of reference to a massive tangle of updating graphs, only a handful of which contain information that's actually germane to the task at hand.
Windows 8 replaces the old view with a new, color-coded 'heat map' grid of data that scales much more effectively to handle large data sets.
The image above shows Windows running on a hypothetical system with 160 logical cores; Microsoft indicates elsewhere that Windows 8 will support up to 640 logical processors (this last is likely an HPC feature). Mousing over a core reveals its identity and the heat map scales automatically to display in the window area. Core affinity can still be set through the Task Manager; this functionality doesn't appear to have changed between Windows 7 and Windows 8.
The advantage of the heatmap approach is that it can be quickly used to identify where threads are executing. while current programs tend to take a "Run 'em wherever" style of approach, AMD's Bulldozer is one example of a CPU which benefits if threads are properly scheduled. Scheduling threads to execute on the same module allows the OS to de-activate unused cores and increase clock speed, while scheduling threads to run on different modules tends to increase performance 15-20 percent. AMD isn't emphasizing the latter fact at all, given that its entire Bulldozer plan revolves around selling modules, but the question of where threads are executing is important to anyone doing performance modeling.