It's completely subjctive stuff. My room has red walls, aqua ceilings, black carpet, gold cutains and gloss black sprinkler pipes. Most of my instruments are vintage, my recording desk is made from an antique table. Mostly it sounds like it would be hellish on paper but it feels warm, comfortable and vast. The walls embrace you, the ceiling disappears and the carpet allows me to control the light. I can make an area go away by just keeping it dark.
I tend to work fast so cable/stand chaos can develop quikly if I'm trying different mic's, amps or instruments for a part. Sometimes the mess can be distracting. I can darken the area and leave it set up without getting bogged down by the mess if I need to move on to something else for awhile.
That's just me. Paint it colors that you like. If you like cool, modern, clean airy spaces then go light. If you like warmer, cozy places then darker. I wanted something that felt completely unlike any other place I spend my time. I love my room and spend hour after hour working in it.
Cogratulations for getting to this point. I was thrilled to death when I was ready to paint.
Good luck, RD