I dont think I have ever 'relaxed' on a holiday, We like doing things so best holidays are ones where we do things. Havent left the UK boarders for a while, come to think of it dont remember a recent holiday.
As for favorite places to recommend, Sorrento in Italy near Naples, Very nice and you can potter about Pompeii and Rome is a short drive. Vienna is a lovely city lots of stuff to do and St. Petersburg is beautiful but to old to go clubbing besides cant go there now, not sure if Americans can either.
As I said we are not a sit by the pool family, but my sister stays in turkey and Egypt at some nice resorts and loves it, cheep to compared to Europe. Hope it helps a bit.