Backpacks are a good thing to bring when traveling to Co, and while in Co. They come in very handy. Hats... The sun can be brutal here in Co. Its hard to say what type of clothing, because here, if you don't like the weather, wait five minutes. It will change! :)
If you plan on doing any hiking, bring good comfortable shoes. Bring lots of FILM! Because the views are awesome! Lots of sunscreen and bug spray. Because the Rays of the sun are extreme... And its always good to be safe. Even if you don't burn!
At night, that is when the bugs come out. So be sure to bring bug spray with a good amount of deet... Especially for hiking.