Oh, now I've got a bunch of captive Canon 400D users in front of me, if you want a tip, here's mine: Buy the f1.8 50mm lens. It's the best value lens you will ever come across. It's less than $100 and will take better pictures of your kids, pets, large objects, etc. It's also a light bucket. It can be a little tricky getting it to focus on stuff at fully open, but that's because the DoF is paper-thin; learn to use it and you'll be exceedingly happy with the results.
Yes, the f1.4 is a better lens, but it's three-times the cost. For the money, you cannot get a better portrait lens.