The 2005FPW is always cheaper than the 2001FP, although it is newer and has better specs. The 2001FP must be more expensive to manufacture, I can't think of any other reason for the price difference.
The 2001FP has a mild screendoor effect (pixel coverage is lower than 1905FP and 2005FPW). It bugs some people, but I hardly noticed after having the monitor for a day or two.
I have always much preferred taller aspect ratios. I hate this trend toward widescreen monitors. It really only makes sense for watching DVDs. Almost any other application is better suited for 4:3 aspect ratio. Look at the windows on your screen right now, I'll bet you've got more windows taking up the full height of the screen than the full width.
Martin