Anne_Louse, the USM in the title only refers to the focussing motor which in the case of the USM is an ultrasonic motor. You would be better off with the 75-300 as the gap between the 55 and 75mm you won't really miss whereas the extra 100mm will make a difference at the telephoto end. Either lens at set to 200mm wil be the same for hand held shots, so the ability to hand hold really doesn't apply at a given f/l. In the final analysis it depends on whether you feel the gap between 55 and 75mm is going to be missed. It may also be worth considering not getting the Kit lenses and opting for a lens of better quality. There is info and some reviews on the various lenses available for Canon DSLR's
here.