Process Explorer (PE) by sysinternals.com is my main one. Process Hacker (PH) is also on-board for those *special* needs that PH will do but PE is too goody-2-shoes to do.
Process Hacker (and Process Explorer) can monitor you CPU, RAM, Disk I/O, Network I/O, and even GPU (although only the integrated one in my NVIDIA Optimus laptop). All as tray icons. I did have to setup an elevated scheduled task for it to show every sensor though. Otherwise very useful nonetheless.
Almost always Process Hacker. Although occasionally some Process Explorer and Process Monitor for certain use cases.
I don't really have the need for a full time process monitor I'm in new program discovery or otherwise troubleshooting. Given the OP's standard, a predominantly hardware monitor with a Desktop reporter: HWMonitor HWiNFO • Open Hardware Monitor, my fav. Development has stalled but continues to provide useful data and configurability and surprisingly works in Windows 10. One of my systems' Desktop widget. Data is dynamic, of course. OHM with SoftPerfect's NetWorx widget pretty much report on what's most important while toiling away at the keyboard.
You hit the nail on the head. Of course I'm also using tools like Process Explorer and System Explorer, but TRM is an "always on" process monitor. That's what I love about it, you guys should check it out. I just put it on top of the screen, and can instantly see if there is any data traffic or if the CPU is being used quite heavily. It can monitor a lot more, but I don't need everything, see screenshot.
BTW, Сhameleon Task Manager seems to be interesting. The free version is perhaps not as advanced as Process Explorer and Process Hacker, but it loads very fast. http://www.chameleon-managers.com/windows-task-manager/
Stalled development un-stalled. https://www.neowin.net/news/open-hardware-monitor-080-beta http://openhardwaremonitor.org/ The desktop gadget is sizeable and offers 4 font sizes. Why the developer insists on the beta classification is not explained. I've been using this so far on seven different systems (currently four, two Windows 7, two 10AU; Core2Duo to sixth gen i3) first with v0.5.