Black & Blue OR Brown & Blonde ?

I'm trying to reinvent myself starting with my hair. My hair is shoulder length but I want it to be long so I'm getting extensions. I also wanna change the color but I have two ideas. I either want the top half of my hair black and the bottom blue or the top half chocolate brown and the bottom half blonde. I'm also getting new contacts and think a clear blue to go with the black or my natural brown to go with the brown. What do you think ? ( I have side swept bangs and long layers). Thanks (: