Should the unit "Ohm" be capitalized or not? For example, "kOhm" versus "kohm" vs "kΩ", which is most correct?
In my experience "kΩ" is preferred, but if you don't have the "Ω" symbol available on your computer then you need to write out the full words in lowercase: "kilo ohm".
See here for the standards on writing out SI units: https://en.wikipedia.org/wiki/International_System_of_Units#Writing_unit_symbols_and_the_values_of_quantities
Edit: The Wikipedia article on the ohm says it should be "kilohm" if written out, which I've not seen in my experience, but I'll include this for full reference.