I love the sound of Italian, especially as spoken by northerners and Romans. It's a musical language, very nice, very lyrical. I have a friend from Italy who speaks it at home, and it's amusing to hear him argue with his mother over the phone (generally, he's at my house, wanting to continue our Hotseat game of CivIV).
I speak a fair amount of Arabic, and I happen to think it's wonderful, correctly spoken. Unlike most languages, it has a better tone to it when spoken by men--it's a language that comes from the throat. It's also quite possibly the nicest language to look at--Arabic calligraphy is wonderful. Written Arabic has this wonderful quality to it; it's flowing one letter into the next, and it looks like the letters are dancing into one another.
Chinese is horrible to listen to, but what it lacks in sound it makes up in the beauty of well-written characters. Simple, yet beautiful--it fits the Chinese well, and the Japanese even better.