Most (if not all anymore) of the large commercial concerns (Giganews, etc.) have in recent years moved their server operations to be as close to the internet 'nodal' (or border-router) points.
As an example, Giganews was in Phoenix for many years, then moved (a couple years ago), to the Reston, VA, area, outside of Washington DC. If you take a look at where the massive main internet routers are, you find the main chunk of them (for the eastern US) are in.... Reston, VA.
Astraweb is located in San Jose, CA, kinda the 'west coast distribution point' for the same.
For London, UK, the major nodal point is, in fact, in London, the 'Docklands' area. And so forth with the other European points (Amsterdam, etc.). But Europe as a whole is much smaller area than North America/US, so things are much more compact fiber routing wise.
As far as the North Atlantic fiber routes (US to Europe), virtually all of them 'land' either on Long Island, NY, New Jersey, or Rhode Island (just to the north of Long Island). The other ends terminate either in the UK or the Netherlands, mostly.