How much will difficulty increase when ASIC miners become generally availible in the coming months? I am considering buying a 5/Ghs Butterfly Labs ASIC miner. My question is, will the difficulty increase caused by large quantities of ASIC miners being shipped in the coming months make the miner in question unprofitable?
I'm guessing this has now been asked like a million times.  Exponentially at first - once hw is available and it becomes more mainstream for the average person to buy asic hardware and setup at their own house...we will see difficulty plateau at a steady rate.  However by the time the plateau occurs, most 50GH/s hardware will only be able to mine a few USD a month...people will have already shifted over to alt-coins and GPUs will be targeting Scrypt Related stuff by that point.  I think we will see a shift of asic hardware from smaller groups  being used on other sha256 altcoins such as PPC, TRC, and FRC.  

I predict Difficulty will hit 120 Million by December 300 Million by June and 1 billion by Dec 2014 at the next block reward halving event.  This won't be because of the small guys I mentioned in the prior paragraph either...difficulty will steadily rise and plateau because there will be dozens if not hundereds of commercial medium and large scale mining operations that came online to 'milk' the system.