I would not book a trip just to shop. But with the current exchange rates for the euro & sterling I'm looking to take a trip.
Yesterday I did mail order from the UK for some stuff that isn't retailed in the USA. The retailer has a USD website in addition to their UK site. Doing the transaction off the UK site with a no transaction fee credit card netted a 10.5% "discount" from the USD site. All kinds of ways to play this.