Speaker choice trouble, PLEASE HELP!

I have been researching and searching for a speaker or speakers for my house in which i can listen in a chill environment with good response and quality of sound, but also for parties dealing with high power levels whilst still retaining quality and a low end response that is clear and felt.

I have struggled to find something that either is not too powerful or wouldn't last long due to heavy usage. I was tempted to get a JBL EON615, but they are way too powerful for the application and not sure that they would sound so good at low levels, nor in a smaller space or do you disagree?

Could you point me into the right direction for speakers with a wide frequency range (can include a subwoofer) whilst retaining quality of sound at higher power and that can be very loud. My budget maxed out is around £400