I thought that the colors were very nice. I agree that you could add some images to it (like in the navbar) I would suggest that you find some kind of background image. I'm sure there are some free sites that offer backgrounds for you (if you don't have an image-editing software like photoshop). It would help break up that "plain" feeling. I would try: http://www.backgroundcity.com/ http://www.grsites.com/archive/textures/ They aren't the highest quality but, they ARE free. If you don't find anything you like there, google it.
