Im looking to replace my canon 18-55 kit lens and i have arround £200 to spend on a walkabout telephoto. which ones do you guys recommend im not too bothered if its new or secondhand just as long as it has much better optics 
a few ive looked at are 
canon 28-135 is 
canon 17- 85 is 
Sigma 17-70mm F2.8-4.5 
Sigma AF 18-125mm 
help would be much appreciated im awful at making decissions  
