I realize that everyone's monitors are different, however that doesn't mean you should just ignore that part of the equation. Just like making a decent audio recording, mixing it to simply sound good "on my speakers" isn't very professional. You have to mix it so that it will sound the best it can on a wide variety of playback systems and environments.
You can't control how your images will look on anyone else's monitor. But if you have a calibrated monitor, then it is more likely to look as good as possible on as many other monitors as possible.
It's the same in audio recording. Professional mixers use professional monitors that are calibrated to have a flat (normal) frequency response. They mix so that it sounds good on the reference monitors, and then it is more likely to sound good on as many other speakers as possible. If you're mixing on speakers with an unknown frequency resposne -- or adjusting colors and tone curves on an uncalibrated monitor -- then the results are unpredictable, unless you have a very good sense for the peculiarities of your specific setup.
Bottom line, calibrate your monitor, and adjust your images so they look good to you there.
As far as sharpening, I personally use Lightroom's default export sharpening set to "low" for most cases, but try a few experiments and see what works for you!