I'm looking for a the best lens for taking wildlife photography. I want to go back to Alaska and have better photos next time. Now with my new T2i camera I need the best lens. The Canon rep on Facebook suggested the 70-200 f2.8L IS II USM. The camera company I spoke with today suggested the Sigma 70-200 f2.8 EX DG HSM II. I'm very new to photography, and I'm getting overwhelmed with all the research and need some advice. Thanks.