I've namechanged for this so as not to out myself. I teach the subject at a university.
History of Art degrees do not only lead to careers in the art world. Art History graduates can still access careers that are open to other humanities graduates, plus many others besides. Many of our graduates do work in public and commercial galleries, museums, the heritage sector, and auction houses. But rather more go on to other kinds of careers: marketing and PR is an area we notably have many graduates going into, but others have gone into teaching, investment banking, law, diplomacy (Foreign Office), etc. It is common to have to do either a postgraduate qualification or various internships after the BA, in order to progress your career. Many public galleries now stipulate a PhD as an essential requirement for a curatorial position.
Languages are extremely useful, particularly if you wish to work in the museums and gallery sector. Many advertisements for curatorial positions stipulate that one or even two foreign languages are required. However, joint History of Art and language degrees can be tricky. There is a large drop-out on these courses at my institution (ie. over 50% of the students drop the language and switch to straight History of Art) - at the end of the day, the joint-honours students are required to attain the same language levels as those doing single-honours language, and so the workload is immense (and chances of getting a first are lower). They also end up mainly doing only the core History of Art modules and not enjoying the range of optionality that single-honours art history students have.
In terms of where to go, there is a lot of variation between departments (rather more than there is with English and History courses). For example, Essex is good for more theoretical / philosophical approaches, East Anglia includes non-Western art, Warwick has a campus in Venice where students spend a term. Also some departments have more of a visual-culture based approach, as opposed to traditional art history. Some are heavily Renaissance-based, others predominantly c20th. It's really important to look carefully at the course structure and options, because they are all very different.