Bell Of Lost Souls has this video from the Canadian Miniwargaming, talking about their response to the new policy. It is also up on Beasts Of War.
The store is closing. Though this is not wholly due to the GW policy changes, it is a significant factor.
I think we're going to see more of this over the coming weeks and months, as stores do the accounts, and decide one way or another if they can stay open. Clearly the US/Canadian based web only stores are going to disappear come June, but for FLGS it's going to be a difficult equation.
The comments threads to the videos make interesting reading, with a mix of opinions on the matter.
Pulling two sides of the story from the blogs I follow, there those advocating a boycott, such as Syko Wargamer, and others getting behind the policy (in part), such as Apocalpyse 40K.
The portion of the existing customer base that is aware of this (because I guess not everyone keeps up with the hobby news online, and GW aren't exactly going to shout about this in store), are possibly going to be pushed towards collecting other ranges.
It's interesting to note that no one really does the big games like GW does. The only real contender (although I'd be happy to be corrected) in the table filling stakes is Mantic, who are going to be the one to watch, to see how they handle this. PP will also see some people coming over to them. Malifaux and Infinity will no doubt also see players looking at their unusual rules systems. Kickstarter is also going to pull people away, with hobby income suddenly more freed up to go into projects, should the right one come along (although that said you'd need something really really big in terms of backers to really change the scenes in stores).
I wonder how much this will affect the meta game in some areas, with players unable/unwilling to fork out for GW's bigger kits, or new forces, and new gamers having a very limited armies in terms of selection and points to draw on.