I have been waiting for this, so exciting.
I have been saving all my larvitar, dratini, lapras, magikarp, relaxo, machop, onix, rhihorn, and on top of that also some that are generally rare and needed for gen4 like likitung and yanma. So my pokemon storage has been close to full for a long time, and now i can sort them all out and send them away for two candy instead of one. All those with low IVs can now go.
So much good candy. I think i will be sending away around 400 pokemon now.
Also, people just got a bunch of lure modules from the silver box purchases. It is now ultra-profitable to farm at lure modules with lucky egg and do some evolving as well. You can evolve every second pidgey and every 4th ratticate you catch.