I loved the x-series, and recently got a new x201. The screen is phenomonally bad. The viewing angle is so poor that if I'm watching a movie on it, there is nowhere I can position it so that I don't get funny colouration on the blacks. Until then, I'd had a dream run with this series. Check your screen quality before getting an x-series...
You should look at the screen on the Z--it is much better than any screen I've seen on any laptop. For reference, I got the cheaper 1600x900 screen; it is exactly the same resolution as my old, cheap 17" laptop.
I can comfortably edit two documents side-by-side in Emacs, on a 13" screen! It really is perfect--anything less would be really annoying now.
