What gauges do you actually look at?

For the most part I watch oil pressure and temp. (besides the clock, which is probably what I check most due to service appointment times and such)
I do have a volt meter, but my AFR gauge will tell me if the system voltage is low for any reason if I don't notice the volt gauge being low.

One thing I used to do on other cars was to use the idiot light switches in tandem with mechanical gauges, then go to the wrecking yard and get a few seat belt or door buzzers.
Then I set it up so if anything did set off what would have been an idiot light it would sound the buzzer instead.
That would inform me instantly of an oil pressure drop, charging system loss, or high temps.
The gauges would show the specific problem.