Whats the standard these days

800x600

or

1024x768

If you are targeting the professional business sector in developed countries, its 1024.

My stats show 80%+ use 1024.

So as not to exclude anyone (well, except those stuck back at 640 x 480), I always design for 800 x 600 (actual design area 780 pixels wide) and, whenever possible, make the design flexible within the browser window so it will widen in larger windows.