Nikkor 35mm f/1.8g vs 50mm f/1.8g

I own a nikon d90 and i'm currently choosing between the nikkor 35mm 1.8g and 50mm 1.8g

I have both and find them to be excellent. With the 1.5x crop factor of your D90, the 35mm gives you the effective view of a 52mm and the 50mm gives you a 75mm view. That means that the 35mm gives you the view of the normal human eye (50mm was the standard lens in 35mm film days) and the 50mm is an excellent portrait optic.

Which one to get? It depends on what you like to shoot. Both are excellent in low-light situations and both will give you excellent bokah (selective focus for great portraits).

My suggestion would be to see what the world looks like with your kit lens zoomed to the 35mm and the 50mm focal lengths. See which is the most useful for you.

Both are good lenses. Both have the same aperture. You've got a lens that covers both focal lengths. Use that to decide.