Well, if this ends up coming to fruition then I guess ghash will be getting a big bump from people because that's where I'll be going as I suspect others will too when the pool closes if it ever does.
I'll go to everywhere, except GHASH.IO. There are lot of good guys still remaining. SLush, Eligius, p2pool, etc...
I'm not sure where slush is located, but Eligius I'm pretty sure is a US based pool and would be subject to the same laws as this pool. P2Pool doesn't support all hard, specifically they have problems with bitfury and S2s to my knowledge, and to my knowledge, no one is sure the S3s will work properly on it. Also, P2Pool doesn't scale very well for small miners. I was recently mining on there, before coming back to BTC Guild, and I would have 24 hour periods with no shares at 250Gh/s. Then there is the variance of possible going days without payment from P2Pool. They way I see it, and I'd REALLY hate to say it, but if the US pools that can at least minimize variance (BTC Guild and Eligius (though I don't know wizkid's stance on the NY Law)) disappear the best remaining option would maybe slush and ghash. I really hope that NY doesn't go and screw the rest of us over by issuing a vague law that will force pools out of business, but then again, it is NY and who knows what will happen.
We have a couple months before anything is really known at this point. Logically, NY state should not be able to enforce this regulation against any company without a nexus in NY, even though the proposed regulation is trying to claim differently. The problem is whether or not there is some federal law/agreement that would allow them to extend their authority. The other problem is that even if they have no authority to do so, it doesn't mean they can't try.
There's also the chance that other states jump on board with the NY regulation. If that happens, there's no guarantee how much time companies in other states will have to react before they become targets.
At least from what we've spoken about so far, wizkid057 (Eligius) appears to believe there is no legal threat to businesses not based in NY. I'm much more conservative, and as such have been preparing for the worst.