Excellent choice Evi! It\'s a great cam, you\'ll have lots of fun with it.
One of your first lens purchases should be the 50mm f1.8. It\'s fast (f1.8) and cheap ($100-ish). If you feel like spending a bit more, the f.1.4 version should be even better, but it\'s also more expensive. For a beginner it\'s more than fine (I own one myself and I love it - I shot some party pics at night w/ ISO 1600 and didn\'t have to use the flash! The shallow DOF is kinda hard to control at that point though so you have to focus carefully).
Filters... When you get some good lenses you\'ll probably want to protect them by putting on a filter. It could be a UV filter or a pol filter.
Another word on lenses, since it\'ll be the biggest chunk of money. Get the fastest lens you can afford. You can always shoot a f1.8 lens at f4, but you can\'t go the other way. If the widest aperture is f4, then you can\'t stop further down. And as you might or might not know, it controls how much light you can capture. You\'ll want flexibility and having a fast lens will give you that.
Other than that, you can read lens reviews at sites like
http://www.fredmiranda.com and others. Just use Google and make sure the lens you wanna buy is actually worth the money.
You also need to figure out what kind of range you want. If you want to be able to take wide angle shots, you\'ll need a 10-22mm for example. If you need telephoto a 70-300mm might be in order. You\'ll soon learn that some lenses have a certain reputation. The Canon 70-200mm is one of them, it\'s a great although expensive lens. And the faster the version, the more expensive it gets. Although I\'d be more than happy with a 70-200mm f4.
Anyway, good luck and have fun.