Things that I'm currently looking for (from more important to less important):

  * 8 hours battery life (while coding)
  * Not scorching hot (the Powerbooks and Macbooks circa   2007 or so were infamous for this)
  * Haswell / 4th gen Intel processor
  * 8GB+ RAM
  * 128GB+ SSD
  * Warranty covers spill damage (this happens to me quite a bit)
  * Trackpoint / nub (I got acquainted with the nub afer spilling coffee on my trackpad)
  * Convertible to tablet with pen (I do a fair amount of illustration)
  * Discreet graphics card
  * Backlit keyboard

I think my love of the trackpoint limits me to Thinkpads, but I'm always on the lookout.