Mr & Mrs Smith
Mr & Mrs Smith is the definitive boutique and luxury hotel guide.
It was set up for a romantic escape with your other half in mind but has since developed Smith & Friends and Smith Ski which as their names suggest include luxury self catering properties for friends and family. In fact, hotels are now highlighted as 'family friendly' where appropriate.
A well designed and visually appealing website, it has a wealth of information including destination guides and printable city guides. In particular I like the fact that every property is personally reviewed and accompanied by a gallery so it feels like you get the true picture. 
An online shop ensures that you can browse through the properties in print as well as purchase gift vouchers and music.
Hotels are sometimes reviewed by guests and I enjoyed reading the review of JK Place in Florence as my husband and I had stayed there and loved it. The guest reviewer was Stella McCartney...