I play MSFS with a PS3 style controller made by game elements (same button layout, wireless, etc) and I enjoy it. It's not the best for "simulation" but if you game on XBOX as much as anyone else, it's just like playing another game.... you get used to the controls even though they aren't the best "layout".
I use the L1/2 and R1/2 buttons for throttle and zoom level. Then it's gear, autopilot, auto throttle, brakes, and point of view changer on the buttons. I use the keyboard for a lot of functions (flaps, open doors, opening instrument panels, etc) and click a few things with the mouse.
I may get a stick someday, but it'll $ and if you already have an XBOX360 controller already available, just go with that. If you're looking for the best simulation, get a joystick. I personally use the game to train my eye for things such as rate of closure, circle of action, angle of approaches, etc, and that can be done on a controller. If I was trying to train my hand inputs on a stick, then I would get one. I'm a helo pilot, and I haven't found a good flying model of the 58D yet, so I'm not concerned about simming the actual stick control.
Also, if I fly fixed wing, it's usually in autopilot (737, CRJ, etc) so I only need the control to get me off the ground.
Sorry- got off topic a little. BOTTOM LINE: I'd vote keep the 360 controller and just have fun playing with it

You might be able to build a more realistic simulation setup by taking it apart, but I don't think it would be worth it. Like everyone else said, but a cheaper one and hack that. In the end, it depends on how you're trying to use MSFS.....