It has nothing to do with your personal preferences. Monitors are used for music production, at least as far as quality is a concern. If quality isn't a concern, then just get a headphone that appeals for music listening and disregard the requirements for music production.
If you know it all, why ask for help? But in any case, it isn't about spending thousands. It's about careful matching of components to get good sound, or at very least the sound you want. Valhalla 2 is a decent choice for the HD 800 if you put in the effort to get the right tubes. I have no idea about the nuprime.
Are you? That's a linear scaling, so not really that bad.