I miss gadgets. they're the best way to see things instantly without having to bring up huge things like the task manager and performance monitors.
For example, I had a gadget that showed the top 3 (arbitrarily set at 3 by me) processes all the time in real time. So if my machine was becoming unresponsive, I could flick my eyes over and immediately see what processes were active. What drove me crazy about the task manager back then was, my system would get unresponsive and then I would open the task manager and then things would calm down. I'd close the task manager and my CPU usage would go back up. Making me think that the hackers were getting clever and dying down processor access whenever the task manager was brought up.
Live Tiles are great for a lot of things but not immediate, instant updates. I think that's why the clock apps fail. The Live Tile cannot update second by second. So the clock live tile will be correct, then fall behind by a couple of minutes, and then be updated to the most recent time and be correct, and then fall behind, etc.
Which brings me to a side point. why the heck did Microsoft not include some time/date function on the start screen? if we're to spend a lot of time on that screen, show the time!