Let me put it this way: the Anniv. special edition is a very nice piece of car and it is worth buying it. But on the other hand, it is nothing really special worth collecting (I'd say the GT3 RS is something worth collecting or even a GT2).
If you like it, buy it because I'm positive you're doing the right thing, buying yourself a great 911. But if you're thinking about resale value, coolness or even collecting it for selling it later at a premium, forget about it.