Lens Kit Canon

Lens Kit Canon
What is a good update of the Canon 18-55 kit lens?

I have a Canon 450D with 18-55 kit lens and I want to upgrade to a higher quality. I am looking particularly at telephoto and super-zoom like the Sigma or Canon 18-200. I do not care if it's a Canon brand lens, provided it has good construction and quality image. My price range is anything under $ 600 (£ 360) What can you suggest?

No doubt you should get 70-200mm f / 4 L.. Http: / / the-digital-picture.com/Reviews http://www.bhphotovideo.com/c/product/183198-USA/Canon_2578A002_70_200mm_f_4_0L_USM_Autofocus.html /-Canon EF-70-200mm-f-4.0-L-USM-Lens-Review.aspx Build quality is excellent, Image quality is incredible and crystal L!. This objective will last a lifetime. I never liked objectives with focal lengths as 18-200mm image quality is always mediocre ..

Canon T1i 18-55mm Kit Lens vs. F1.4 Lens in Low Light