Thank you guys! I appreciate all the feedback 
Thanks bro. I would personally go with the one where you manually zoom the lens with your hand, as this is a much quicker and more effective way to take photos. If you get one with digital zoom then you may miss out on the shot you're trying to take due to the delay of the zoom. This is why all of the top level DSLR's use manual zoom. It's extremely simple to adjust the zoom by hand, all you have to do is twist the lens and you'll see it zooming in and out through the viewfinder. You can also get the zoom MUCH more precise than a camera that's equipped with a digital zoom. Honestly bro, you won't regret it 
As for the interchangeable lenses, you may not think you'll need a bigger one now, but trust me, they come in very useful. Most Canon DSLR kits these days have the option of being bought as a twin lens kit, where you get a standard lens (usually 18-55mm) and a telephoto lens (usually a 75-300mm lens). The telephoto lens is perfect for taking photos of butterflies and flowers etc, or even if you want to take a detailed shot of the front of your car. It doesn't just have to be for long distance shots, although it does come in handy for those too. So in my opinion, go for a twin lens kit, in either the 550D or the 600D.