Dual Monitor Setup 2560x1920 and 1920 by 1200?

I currently own a Gateway 1920x1200 and I run a dual monitor setup with another 1280x1024.

I am sick of the 1280x1024 and want a bigger monitor to accompany my 1920x1200.

I first need a decent dual link DVI video card...(BTW how much is a decent one and which model would be a good one?)

I am considering getting the Samsung 305T or go the cheaper route with another 1920x1200 (not sure which one).

Either way I want a dual monitor setup.

Which is the superior Desktop experience?

My main reason for getting the monitor is not for games, but for simple desktop aesthetics, and efficiency of use for certain programs like Excel, Photoshop....Noting too heavy in terms of usage, but I generally want a better computer experience and visual.

Is it worth getting the Samsung at 1200 or should I just get another 1920x1200? Would that be worth the upgrade? Any help would be greatly appreciated.

Thanks