My observation is that the displays are mediocre at best across the entire MacBook and MacBook Pro lines. The LED-backlit 15" MBP is the best of the lot, but it's still totally inferior to my desktop display. The rest of the MB and MBP displays are "merely adequate", or something like that.
Otherwise, I second Ken Bennett's point of view. All things being equal—and they seldom are—the MB is a much better value than the MBPs. You want to run Photoshop, and Photoshop needs RAM. PS needs so much RAM that it also needs good disk performance for virtual memory. As I'm sure you know, the larger the image files (spatial resolution and layers) you work with, the more you're going to feel the RAM pressure. If this laptop is a supplemental tool rather than a desktop replacement, it might not much matter. If you're planning to do all your image manipulation on the laptop, it might matter a whole lot.
Note that a major upgrade to OS X is shipping around the end of October and changes to both the MB and MBP lines are likely in the ensuing months. Some of those changes might arrive before the end of the year, but I wouldn't be surprised if they do not, since the lines were last updated in May and June, respectively.
White Balance so easy, even our 5 year old can do it.- Melissa Strickland