I have tended, for the past three editions, to treat Con as a dump stat. Granted, I rarely create melee characters, but even when I do I tend to treat Con as tertiary at best. Note that "dump" is not necessarily where I put my lowest score, but rather where I stick my 10-13 rolls. Single digit scores are penalties and therefore interesting, and D&D tends to treat Constitution in a fairly boring manner compared to, well, basically every other stat. If there were some fun skills to play around with, or even a good spread of class features that rely on Con, that'd be something. But there's barely anything. You are tougher to kill. Fin.
On the rare occasions I make a character that is meant to be tough to kill, then I certainly prioritize Con. But most of my characters aren't really designed that way to begin with (from a narrativist perspective, much less from a gamist one), and given the choice between 2-3 extra HP per level and a +2-3 bonus in a slew of interesting skills that would add more depth to my character? That's a no-brainer for me.
Not that I don't understand the gamist appeal of not neglecting Constitution; and when I roll characters in Baldur's Gate or Icewind Dale or KotOR I give it the attention it deserves there. But that's simply not the approach I take when I sit down at an actual table to play.