I have the Bug-A-Salt, Thermapen and Phillips One Blade that have been mentioned on here. All are great gifts if the person doesn't already have one.
The Bug-A-Salt is great for bugs that have landed. The laser pointer attachment makes it very easy to aim. We also have an electric tennis racket looking thing for knocking them out of the air. The battery is iffy, but it works well.
I got the Thermapen based off recs here and it is seriously badass. Almost instantaneous read of meat temperature. It's a massive upgrade from what I was using previously.
So far, the One Blade Body with the guard works well for safely grooming downstairs. I haven't tried it for anything else, but it seems like it would work well for short stubble on the face, or they sell one with an adjustable guard for beard trimming.
If I was picking one off that list, and it was in the budget, I'd go Thermapen. If you check out the thread on meat thermometers, you find one of the rare moments of complete consensus on this board. Everyone with a Thermapen recommended it highly.