One of the things I love most about Paris -- my very favorite European city to visit -- is the sheer plethora of museums. I've been lucky to spend a lot of time in Paris on several different trips, but I have not come close to visiting them all. The Louvre and the Orsay are on everyone's list, and I certainly spend much time at both, but here are others I enjoy.
Musée Rodin: I first visited this one over ten years ago, before they built their new visitor pavilion and everybody else found it. It's a treat, such beautiful sculptures and gardens, best visited on a beautiful day when you can sit outside among the roses. (And on a weekday, when it's not super-busy.) Now with the new pavilion they offer more exhibitions; I caught a great one of Rodin's collection of Japanese prints last year. They have a few van Goghs, including one of the Arles harvest scenes and my favorite of the Père Tanguy portraits.
Musée Marmottan:This one's a little out from the center, but worth the trip. The Monets on the ground floor are the stars, but there's plenty else to see. My first visit here, I'd been to Giverny the day before, and that turned out to be a happy order of things. A progression of Monet's waterlilies are hung, from the more naturalistic to the increasingly abstract. I found myself loving the late-period waterlilies that usually are more ignored. "Impression:Sunrise" is here, the painting that gave its name to the movement.
Musée Gustave Moreau: This one was at the top of my list last trip, because I'd never been. Fantastic. Moreau's former home and studio form the museum, and the studio walls are hung floor to ceiling with Moreau's incredible visionary paintings. A particular treat is the cabinets filled with his drawings. Most museums keep drawings locked away in storage for their safety, but here you can look at them in the special cabinets. They give a wonderful sense of the artistic process.
Musée Délacroix: In the same vein, on the Left Bank you can visit Délacroix's former home and studio and see some of his works there. This museum is best visited after you've seen the most famous Délacroixs at the Louvre.
Musée Guimet: I was blown away by this museum of Asian art last year. It was much larger than I expected, and I hadn't allowed enough time to see it all. I usually eschew audio-tours, but I took one here, and it helped to fill in the large gaps in my knowledge. (We didn't have an Asian art professor at my university, sadly.) The Cambodian and Indian material was my favorite.
Musée Cluny: I usually stay in this neighborhood of the Quartier Latin, so the Cluny is typically on my list for a re-visit. Some of the displays need updating, but the objects are so interesting one can manage without snazzy labels and wall texts. The highlight is the foray into the once-Roman baths, not to mention the famous Unicorn Tapestries.
Musée Carnavalet: Like the Moreau, this was one I hadn't been to until last year. A fantastic treasure-trove of Parisian history that kept me busy for quite a while. I particularly liked the rooms relating to the Revolution, a period that has always fascinated me. Unfortunately, some of the 19th century rooms were closed on my visit, so I'll have to go back next trip.
Petit Palais: I think this venue is better known for its special exhibitions, but the permanent collection is nothing to sneeze at. Naturally I like the antiquities best; they have some quite nice Athenian vases.
Musée de Montmartre: On Rue Cortot, partly occupying a building once lived in by Renoir while he painted the Moulin de la Galette. I love this small museum with its Toulouse-Lautrec posters and its recreation of a Montmartrois café. It's a delightful peek into the unique culture of this arrondissement.
Bibliothèque Nationale, Cabinet des Médailles: this one is really for hard-core antiquities fans. Some fabulous Athenian vases are here -- famous ones -- and the incredible Roman cameos are worth the trip. The celebrated Grande Camée de France, formerly in the royal collections, is here, and it's much bigger than you think it is going to be.
Even in the Louvre and the Orsay, there are less-visited corners worth seeking out. The Louvre's ancient Near Eastern collection is one of the best in the world, and yet you're likely to have the galleries to yourself. Ditto for the Islamic art galleries, decorative arts collection and the Campana collection of Greek vases. At the Orsay, I love the Art Nouveau section on the quiet middle level. One of Vincent's paintings of the Saint-Rémy asylum is tucked away with the Kaganovitch collection on level 4, away from the rest of the van Goghs and the accompanying teeming crowds with camera-phones.
Museums I still need to visit...the Musée Jacquemart-André, the Musée Maillol, the Musée Cognacq-Jay, and out in St-Germain-de-Laye, the museum of prehistoric artifacts. Guess I have to go back sometime soon!