I'm not sure. I do enjoy glowsticks while tripping. So, perhaps you could incorporate some glow sticks. All in all, I personally prefer dimmish lighting. I'm sure it varies for everyone. While it's no biggie for me, flourescent lights are a bit "bright" for me while tripping. Overall, I don't really like bright lights while tripping. Doesn't bother me much, but certainly doesn't make for the best tripping environment for me anyways. So, I'd say dim lights.
To me, the coolest room possible while tripping....... and I must say the mere thought of looking at this while tripping sounds absolutely ecstatic....... a room with large glow sticks/lava lamps as lights. AND psychedelic artwork, especially that psychdelic meme you see with the woman holding an acid tab along with some psychedelic images/tapestries. Just completely cover the room with fractal style psychedelic artwork and light the entire room with glow sticks and lava lamps. Also, maybe have a projector or something that has subtle, dim lights that change constantly yet very slowly and gently. The glow sticks/lava lamps and the projector would need to be pretty dim though, like the level of lighting you'd see in a club or something sort of. Yet enough to see well. Since you obviously trip on a regular/semi regular basis if you're posting this, I'd say the best test to see if your psychedelic room would be awesome while tripping is to experiment and play around a bit and see what you see as a beautiful/fascinating space to trip in while you are tripping.
Oh, and I agree about the Christmas lights. That may be a different theme, but I feel like while tripping, it might be kind of cool to include the Christmas tree, maybe a mini one though. That would be great. I would really like that while tripping. This is just going on what I think would look best while tripping. And play soothing, calm music in the room that has meaningful lyrics that would be uplifting and likely to lead to a positive trip. Just my opinion, and I'm not tripping right now, so I would just experiment with things and see what makes for the best tripping room. I never paid much attention to the room, paid attention to the people I was around/the general setting but never the room aside from that I generally don't like bright lights, though I never really even paid a lot of attention to that....... but yeah, as far as interior decor for tripping I'd say bright lights are best avoided. IMO, the music that's being played is FAR more important than the room.
And you know what I KNOW would be amazing. Plush blankets would be AWESOME. There were times that I wore my Mom's plush sweatshirt while tripping......... because the plush feel of it was literally ecstatic while tripping. Just the texture of plush would be awesome while tripping. Truly amazing and beautiful. Unfortunately, I think my Mom thought that I was wearing her clothes because I was a crossdresser or something though. She didn't say anything but had an odd look on her face when she saw that I was wearing it. Wasn't anything like that though, just the fact that anything with that plush texture is just truly BEAUTIFUL and AMAZING while tripping
IME, if something looks "cool" while high, there's a good chance that it will look absolutely beautiful and wondrous while tripping