[ZrByte]

Originally Posted by Matt D

Ordered the disc version last night Not immediate like buying a key / digital download, but *cheaper*!

This is good:

PC Gamer: Diablo 3 review as it happens

If past blizzard releases are anything to go by you could download the digital edition now, get it installed and patched if it needs it and just apply your CD Key when it arrives.
A friend of mine has my game CD for another game I keep mentioning here so he could play with my guest key since his internet connection was fine for playing the game but would take an age to install. I formatted my machine a few weeks ago without thinking that I didn't have my CD back and just installed it from blizzard.com instead.