You have a nice geometric, somewhat masculine look going here. I would play that up. I don't think you need to change the wall or carpet color as they seem to be a nice neutral background. Are they cream? is the purple more plum? and is the blue more of a steel blue/gray? The furniture is chocolate brown? I love the striped pillow on the chair. I would layer a wool steel blue/gray area rug and then play up the blue/plum in the pillows. A wool plaid or blue gray herringbone in a couple of throw pillows (replace a few of the solid color pillows) could help to pull it all together. Kind of like the colors in the picture of this bag. Adding brown leather cording would be a great compliment on the pillows. (Not sure the area rug in front of the TV is adding anything)

I wouldn't do navy but there must be other options than white. You have white tile so it might be too much of an expanse of white. If you are decorating around that lovely rug ( or are those set in tiles?), why not choose a lighter color from it and paint that color. ( A pale blue, a beige or a tan).

I'd suggest dark red curtains if you need curtains at all -- the windows are beautiful as they are, and I'm not sure whether some kind of blind might not give you the ability to darken the room when you want to. On the wall, if you are real fans of any movies or TV shows, three big posters would be fun. Otherwise, I would still suggest using three pieces of art there of that size, all equal in size and somehow relating to each other. Three floral works, or three works in the same style, perhaps. I think a large plain textured rug in a light neutral from one of the cushion fabrics would tie the space together well. You might also consider a lovely low coffee table on the rug to lay out your snacks and drinks for serious media nights.

I select these colours with the help of other houzzer and expert professional advice and discussion. I also got help from colour paint catalogue. Is it looking good or not? Is there any problem with these colours and their combination. Please guide me in this regard.