I've used the X-Rite Eye One Display 2 hardward monitor calibrator on a 15"MacBook Pro with the old non-LED backlight. It made a HUGE improvement, even over what I could do visually with my 27-year old eyes using OS X's ColorSync calibrator. Yes, technically it is impossible to get 100% accurate color on a laptop's screen, but they sure are close to true now that I've calibrated the screen.
I would highly recommend the Eye One Display 2, especially if you are trying to calibrate your color for print output. This particular device comes with an ambient light diffuser that lets the device measure the color temperature of your print viewing area, and to then match your monitor's output to match that color space. So, in my case, I always view my print proofs in my office during the daytime with the window's shades up. When I do my Eye One calibration, I raise the shades, and take a measurement of the room's ambient light, and the EyeOne software matches my monitor's color temperature to match it. Therefore, when I look at a print in this room, and try to match it with an on-screen color, it will be an accurate RGB representation. The EyeOne isn't the only one with an ambient light head, but my research led me to it above all the other products out there.
A word of warning when you're looking for this. The manufacturer is a company called X-Rite, but they've licensed it to Pantone as well, so sometimes you'll see it branded "Pantone Eye One Display 2". In addition, the company X-Rite was called "GretagMacBeth" until fairly recently, and you'll still see it called that on some message boards. ALSO, the Eye One is often called the "i1". They really need to get their products unified under a single identity.
Hope that helps you out.
