So I'm looking to get (or ask Santa to get) a telephoto lens and a Flash. I don't have any as of now so I'm pretty much in new territory on what's good and what's not. I have a Canon Rebel XT and I'm looking for a Telephoto Lens around $300-$400 possibly around the 300mm range. I know the IS lenses are nice, but it's going to be way too expensive. Is IS necessary or is just a nice (but expensive) addition? As for a flash, I haven't done a whole lot of research so I'm hoping you folk can help me out here. What kind of specs do you look for in a flash, do I just get something Canon made? Thanks for all the help!