It doesn't matter what size the screen is when I want to reach the corners. I just slam my mouse to the lower left and I know exactly where it will be.
Why is this downvoted? This is exactly the usability argument for having a bottom-left aligned Start menu, and it's based on robust evidence about how easily users can select controls of different sizes and in different places with a pointing device.
If you have such a large screen that you can't quickly move your pointer to anywhere on it, I suggest that you have a bigger problem with your system than where your Start menu appears.
Not that i disagree, but who actually clicks on the start menu using the mouse? Just use the Windows button on the keyboard where your left hand is likely resting already.
Fun fact btw, in win 95 the border of the start button was not clickable, so slamming into the corner did not work because of that 2px border. Microsoft was proud of presenting this feature in later versions, don't remember if it was in 98, 2000 or XP.
