It all depends on what you shoot. If you’re going into landscapes, consider a wide lens (I have the Tamron 11-18mm and its awesome). If you’re more into portraits or need a good all-round lens, get the “nifty-fifty” Canon 50mm f/1.8 lens for about 100 euro (this lens gets good reviews everywhere and is a great beginner’s lens). If you want to photograph wildlife, sports, etc. where range is an issue, consider a telephoto (eg. 55-200mm). In an case, buy the best you can afford. One lesson I’ve learnt is that all the rest of your equipment means nothing if your lens sucks.