Things to keep in mind,
Miners start moving away from pools start to reach close or on 50%..
Secondly, the bitcoin community never sleeps... You can try to pull off a 51% attack unnoticed, but depending on how quick you are you are fighting idealists... So if you wanna attack the network you gotta do it in quick succession, or these crazy guys will find so much hashing power... that you need to go back to production.
If you have near unlimited resources you can still pull of a 51% attack and attempt to destroy the network. But unless you want to destroy the network... a 51% attack is useless... Stealing other peoples coins, instantly makes all coins useless, attempting double spends same.
Keep in mind though that the bitcoin network is still rising with more than 20% hashing power per 2 weeks...
All this together means that you would need to pretent for a long time to be serious player in the industry, without getting caught. Even then the chances of you pulling it off... No-one knows...
Say someone was serious, and we saw a chunk of 45% unknown... knc, asic-miner, avalon, bfl they all aren't gonna risk that bitcoin goes to zero... They will turn on any hashing power they have in stock to compensate, maybe even delaying customer shipping. And the community will love them for it as they saved bitcoin. (good chance I still missed some mining companies)
So pulling off an attack now, has you fighting against those parties to start of with, then the idealists will start putting their GPU's back to bitcoin. (all alt-coins will see a big drop in hashing power)
So if you can beat all of this right now, you can pull it off. However a year from now, the market will be saturated with the latest gen ASICs, at which point I don't even see the US gov pull of a 51% attack, due to the sheer volume of hashing power needed. (you're going to be looking at millions of latest gen ASIC to pull of a 51% attack)
So all in all... not to worried... the gov's are still to busy with laughing... (some appear to be getting it, but looking at the history, they are just doing their old business... for example India)
By the time they realize... its going to be late to stop it.
Beyond government's, we don't have to fear many, as almost all humans or companies are motivated by money or ideology, the money incentive of bitcoin is easy, and as far as ideology goes most are fighting for freedom, which clearly lines up with bitcoin. (what's more free than being able to send money to anyone you want, without anyone being able to tell you no)
So yea, its FUD as always