Next week, I'm going shopping, and I'd love some advice on some equipment. I'll have about $1600 to spend. I have a Digital Rebel with the lens that came with it, as well as a 50mm/f1.8. I also just purchased two studio strobe lights. My wish list includes: Flash (I've pretty much settled on the 550EX unless you can convince me otherwise) Another lens (I shoot mainly pics of my kids, but will also be taking a photography course, so suggestions are welcome) Background equipment and backdrops (are there good brands?) What would you buy?