While in Barcelona, I had a couple of really enjoyable stays each at the Hotel Arts Barcelona (part of the Ritz Carlton chain), and at the Grand Marina Hotel (a beautiful Pei-Cobb designed complex). Both are gay-friendly.
The Hotel Arts is located on the harbor in the heart of the former Olympic Village. The subway stop is a 5 minute walk. It has undergone a complete renovation last year, and has one-upped the Ian Schrager hotel chain in terms of decor and ambiance--esp. in the common areas. It also has a well-equipped, two-story gym with spa that's rarely found in Spanish hotels. Service is impeccable.
The Grand Marina Hotel (The Maritime Group) is more conveniently located at the ferry/cruise-ship terminal at the end of the main boulevard in town. It has an ultra-modern nautical design theme, and part of a mixed-use complex penned by I.M. Pei. The rooms are spectacularly decked out in rosewood and the bathrooms are a marvel of carrera marble, glass, and chrome. Whirlpool spas are in every room. I've enjoyed great service here as well, and the meals here are a feast.
Hope you have a great time in Barcelona--one of my favorite European destinations.