Re: Centering my website...
No -- if you've set the width to 1280px, then the container div will always be at 1280px wide, so on any screen less than about 1310px wide there will be a horizontal scroll bar. (Don't forget that browsers have "chrome", like the vertical scroll bar and application window borders that take up some screen space as well.) If 1280px is the widest you want the page to go, then set 1280px as the max-width instead of the width.
“Beware of bugs in the above code; I have only proved it correct, not tried it.” --Donald Knuth
"It was as if its architects were given a perfectly good hammer and gleefully replied, 'neat! With this hammer, we can build a tool that can pound in nails.'" -- Alex Papadimoulis (on TheDailyWTF.com)