I think it's insanity to add more HW at a point in time during which your investment will likely never be fully recouped (unless gambling on massive future price hikes) but if you or your investors have the money then go for it
People like Vladimir bought their hardware long ago and have made profit for months, I can understand keeping them online,
adding 100ghash/s more capacity at this point seems nuts but you've made your calculations & predictions
No investors - I take it out of our cash flow, and I always say - if that blows, I am a HUGH seller of used graphics cards into the december market
![Wink](https://bitcointalk.org/Smileys/default/wink.gif)
But "a datacenter" does normally not work - I figured out I save with 16 machines more moeny in electricity than it costs me to rent the place
![Wink](https://bitcointalk.org/Smileys/default/wink.gif)
Problem is for me - I run a company and make quite a lot of money. Runnign 3 servers just is not worth it. I HAVE to make at least 500 USD a day to make it worthwhile my time.