I'm a Canon guy and just went from a 300D to a 40D. So far so good. The extra speed and control + live-view options really opened up a number of creative options.
While a new camera will offset the boredom, the real cause is often lack of interesting subject matter or inspiration. Why not take a class, or visit a bookstore and get a book on photography to see if inspires.
2006 330i - ZSP/ZPP/ZCW/i-Drive/Steptronic