My main thermometer for the last 30-odd years is the Taylor Precision Products Digital Cooking Thermometer/Timer
. I first reviewed it on Amazon more than 20 years ago, and I've updated it several times.
My review is easy to find, because it's the first of thousands, but in short, once you know its limitations (and have a spare probe on hand: they sometimes don't last long), it's a reliable tool. I can't understand why they haven't yet come up with a probe cord that can handle more than 392F, because I often exceed those temperatures. I like to stick it in the centre of what I'm cooking and leave it there ready to alarm me when it reaches the temperature I set.
I've tried cordless remote thermometers, but have never found a reliable, simple one. I don't use "instant-read" thermometers, because the Taylor only takes five seconds to give an accurate temp. The only other thermometer I use is a $20 infra-red one that is accurate up to 900F, but I've pegged even that one with my pizza oven. It also has the great advantage of coming with a laser pointer, so I can also literally drive the cat up the wall.
Oops: I sometimes also use my $200 Auber PID controller
as a lab-quality thermometer, but its main job is running my smoker. (While getting that link, I discovered they now also make a thermocouple dual-probe thermometer
for less than $200 in which the probe is rated up to 900F. I's gonna git me one of dose, ya betcha.)