Not sure culture vultures is quite right but still...Waterstone's appear to have the country covered for launch parties (although some miserable shops are just going to open at midnight, take your money and close again )
Some shops have breakfast events on the Saturday morning, and some also have events the week before, but the prize for effort goes to Milton Keynes who start at 8pm on the Friday and have different events all day on the Saturday - the staff will be on their knees!