I'm seeing this more and more recently. If I do a search for something (I'm based in the UK and using google.co.uk searching 'the web' rather than just UK results), I used to see primarily UK-based results - especially if the search was product/shopping based.
Now I'm seeing lots of US sites in the results, and as a user it's very frustrating.
For example if I select a 'year' then a car make and model I'm seeing a page that has seven results from US sites and only three from UK sites isn't useful at all.
From a webmaster's point of view it's also highly frustrating. The question is if this is a temporary situation or if Google has truly lost the plot in terms of some of the results it's showing.