We all play on monitors ( mostly ) and i was wondering if there are any special mods or addons one can use if you have a monitor that supports either 120 Hz or an ISP panel for example?

I have seen a few videos where the colors were just horrific on my screen, and that got me thinking that we all see the outcome of our graphical setting differently depending on what hardware we use. A video from one person may look terrible due to what monitor one uses.

I play on a Samsung 23" LED S23A750D at 120 Hz with an Nvidia 570 card.

For instance, when choosing between the high res texture-packs..would i benefit more from the official one or from the 2k version?

This isn't really a mod issue. What you see on your monitor is really up to your calibration, which can be done from the device or the video card drivers, or by using a third party program.

Here's a helpful website for that:
http://www.lagom.nl/lcd-test/

Of course it someone made something by using a horribly calibrated monitor, it would look awful to everyone else.