Apologies - no idea how to desribe this:

I have a new 24" screen - it's awesome.

Now for Windows 7's best feature - snapping windows to the left, or right of the screen by dragging it to the left or right.  What I want to do is make it by default so it doesnt snap to taking up 1/2 the screen, rather, mayby 2/3 and 1/3 respectively.  I.E. I can have my email client, word whatever, snapped to the left to take up 2/3 of the screen, and a PDF, Webpage or whatever snapped to theright.

Can I do this quickly or am I doomed to doing it manually?

Cheers