Those who have gridseed units (and didn't pay stupidly much for it) will be able to survive a much larger profitability drop before reaching a point where they have to shut down.
Except, of course, when the new ASIC farms come online in the next 3-6 months, and everyone switches away to nScrypt and other algorithms which these ASICs can't handle.
At the moment the ROI for a Gridseed is in the 9-12 month range (accounting for difficulty), and I have little faith that straight Scrypt based coins will remain profitable for that long.
I think GPU mining will remain the best long term bet for quite some time now.
I honestly don't think crap coins are ready for ASIC, this isn't bitcoin, most people are middle mining them for something tangible. Once ASIC comes on the scene it will just kill the coin. Bitcoin had really good distribution when ASIC hit the network, the crap coins will die fast when ASIC miners come on the scene... and I doubt they will be able to recoup their investment, the market will drop fast. Right now its working because of the distribution, screw that up further and it will be a very dead horse.