I haven't lit the Bandai kit, but I've lit probably a dozen of the AMT-ERTL kits in the past, using nearly as many different approaches to lighting them. The X-wing is fairly easy to light and it's a good project for anyone who hasn't installed lights before.
With the last one I built, I used the VoodooFX lighting kit for the sake of simplicity. The kit includes a basic circuit board, wires, resistors, and LEDs, as well as simple directions. Solder the resistors to the board, then attach the LEDs - very easy to do. Having the resistors on the board itself, rather than soldered in-line, frees up a lot of space inside the model and it makes placement a snap to do.
Plus, with twelve lines running out, the board allows for lighting the cockpit and the R2 unit, as well as the engines. You can (with a bit of trimming) fit the board completely inside of the model, or squirrel it inside a display base and just run wiring up the mounting pole.
Lots of companies do similar kits (Sterling, TenaControls, Madman, etc), with similar approaches. The Tena kit features a pre-built circuit board with screw terminals, making it easy to assemble, but you need to install resistors. Great kit, but it is a little expensive. I went with VFX simply because the boards in their kits can be modified for other projects and components can be swapped around for different applications.
http://www.voodoofx.com/product/xwingmodellightingkit/