Buying a lens brings up many questions. Which you have already asked yourself.And i have to agree with WD , you wont get all you asked outta one lens. I too have the Canon XS with the lenses you mentioned. I too want to add lenses to my gear ( all the time ,just like the rest of us). If you want your camera body to "click click click" like a pro model you have to know first what it's capable of and understand the theory of "light" coming in through what you have. The longer a lens the more shake will appear and your photos will be blurry. Get yourself a tripod and you will see a difference. I have a fishing buddy that advised me once after i wanted a new rod like the pros, " a thousand dollar rod wont make ya catch bigger fish if ya don't know how to use it". The people on this sight are great for tips and from learning from. My photography has gone up way better since i've been a member here. We all want the top of the line equipment.