Alright, let me fire up Final Cut Pro and show you what it means for us to have a higher resolution display.
The following pictures are quite large if you're viewing them on a 13" macbook pro so I'm going to direct link them and not have them inline.
The setup:
Final Cut Pro editing 1080p footage, 16 minute project.
Here is Final Cut Pro in standard view, as seen at 1280x800, the resolution of the 13" Macbook/Macbook Pro. Notice the footage is displayed at 22%. Not big enough to work with.
http://img706.imageshack.us/img706/1900/1280av.jpg
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Now, here is that same screen, but with the screen res increased to 1920x1200. Final Cut Pro is taking up exactly 1280x800 pixels of space. Notice the screen real estate gained.
http://img203.imageshack.us/img203/5107/1280in1920.jpg
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Now let's expand Final Cut to use the space. We have many options from here. Here it is in the same configuration as was displayed on the 1280x800 shot. Notice IMMENSE amount of timeline workspace gained, as well as a bump in footage size to 33%.
http://img638.imageshack.us/img638/3799/1920standard.jpg
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Finally, we arrive at how I work: in Two Up mode. This allows the both the preview and the play windows to be displayed at a decidedly massive 50% (100% being 1920x1080, basically the whole screen).
http://img638.imageshack.us/img638/8597/1920twoup.jpg
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As you can see, screen resolution is more about fitting more on the screen at one time, easing up your workflow and making things less cramped. It's a biiiig difference.