I would probably definitely go a better lens before changing cameras. I used to have a Canon 550D and like you, I felt like I knew what I was doing with it too easily and wanted a little bit more excitement! So I got a 5D Mk II and I want to be buried with it. But I also got a pro 24-70mm lens which totally rocks my socks off. I have a nifty fifty, which aren't expensive but are great, and also an 85mm 1.8 which is a cheaper 85mm but fab for portraits. Get a lens purely because it can go on any new body you wish to get in the future. If you love photography, go on forums, do a course and delve into it a bit more. I did for a while, but don't have much time at the moment, but once I've moved house (again!) I plan on getting into it more seriously. Have fun with it and good luck