Basically it all depends what you want them to do. Do you want them to compliment your keyborads and sound good or do you want to know what your keyboards really sound like and you want accuracy. I also depends on jow much you want to spend. KRK are good for the money. I have Yamaha HS8 and I like them. They are pretty accurate and don't color the sound if that is what you are after. If it's just home use you probably don't need too much power anyway. Better go for quality. My hs8 can go really loud.
Why don't you try maybe real pa speakers like Yamaha dxr8 or 10. They are great little speakers and you can use them as a PA speakers too. You never know.
For the home i prefer monitors, as they make the sound as i have set it up on the keyboard... In the end, i just prefer setting up the sound inside the keyboard as i want it, instead of adapting the sound of the keyboard to how a PA changes it...
I just prefer the naturall sound of monitors above the charasteristics most PAs add by default, and i can just eddit the output of the key to reach the same effect as the PA if i like a certain characteristic in my sound..
Both the KRK and the HS8 are topknotch monitors, but i never got my KRKs above 20% of their power, where in general speakers function best soundwise at about 30% of their max power, so i guess havibg about 2/3th of my 10 rokit should do the job...