IMO and for the quality of my vision, there is no reason to get a 14 or 15 inch XGA screen. XGA is usable on a 12 inch screen so you might as well save the size, weight and power usage. A larger screen only justifies itself if it has a higher resolution. I think a 14" SXGA+ (1400x1050) is the current sweet spot for resolution vs. size.

If you are looking for an ultraportable the Fujitsu P5000 looks like a very nice machine. It's the current object of my tech lust.

-Dylan