Alternative activity monitors for OS X?

I’m a bit intrigued by the new detailed activity monitors and progress indicators in Windows 8 (copying files, the task monitor, network activity, etc.) It got me thinking: surely there must be some **better alternatives to the built-in *Activity Monitor.app?*** “Better” as in more detailed and nicer graphs. Specifically, it would be interested and see percentage **disk I/O** (out of disk capacity), memory usage, and CPU usage in the same nice way The Building windows blog has an article detailing the new Task Manager in Windows 8. I just think that OS X’s task manager — which I have always found superior — just doesn’t cut it anymore compared to what is coming in Windows 8.