We use that lens as our everyday lens on our Rebel XT, the shots are gorgeous! The only downside is that for aquarium macro shots a 100mm plus focal length would get you closer, if you want a dedicated macro lens. On the other hand the quality has been so good I don't have a problem with cropping.
This is my next lens
http://www.bccamera.com/index.php?ma...roducts_id=304