When -I- say sparring, I mean training against an uncooperative opponent within the confines of the drill that I'm practicing. In my own training I see boxing, wrestling and ground grappling as sparring AND as drills for a MMA stylist, they are a training drill that confines attacks within a limited range so that each player can focus of building skills.
Some posters on this thread are assuming that sparring is an all out flurry that doesn't train anything but instinctive reactions or skill-sets that have already been previously learned. My gym does sparring with beginners that consist of nothing but jabs and jab evasions in an uncooperative manner, yes it's a drill but it is sparring. Both players are trying to hit each other even if it's a playful tap within the small range of techniques that are legal within that drill.
I highly recommend the writings of Matt Thorton, and the "Aliveness" training method of Straight Blast Gym. After experiencing it I can no longer train a rote drilling method and expect to gain practical skills.
Matt Thornton's Training Blog
http://aliveness101.blogspot.com/