It's a difficult choice. My favorite ones are Caroline Trentini, Isabeli Fontana and Gisele. Yeah, three, because I can't decide who's my favorite.
Raquel is a wonderful model too, like Ana Beatriz Barros, Alessandra Ambrósio, Adriana Lima, Flávia de Oliveira (I miss her!) and Izabel Goulart.
Now I'll explain why:
Caroline Trentini: she's the most adorable model ever! She's a great model, her catwalk is perfect, her photos are wonderful (even when she's jumping! hasuhas), she has an amazing personality, and, of course, an amazing body and face. She's not that skinny and she's curvy. She can do everything, VS, high fashion, no matter what, and she does everything with so much passion and love! Everybody who has already had the opportunity to meet her says she's really nice, polite and cute. Last season she gave all the money she earned during fashion weeks to an institution that takes care of children with cancer!
Isabeli Fontana: one of the sexiest models in the world in all time. She's really beautiful! Nobody else in the earth has a body like hers after having TWO babies. She deserves to be the number 1 of the world, because she was out of fashion scene twice, and she really worked very very very hard to get her space back. And the most impressive thing is that she comes back even better and sexier! When she had her second baby, I made the huge mistake to think she wouldn't go back to the fashion world anymore. Or she wouldn't be sucessful. But fortunately she surprised me (and the rest of the world) and so there she is, at Valentino, Cavalli, US Vogue, Vogue Paris, Vogue Italy... Hope to see her a lot in the next years!
Gisele: Gisele is the last supermodel of the world. She's very sexy and she made a revolution in the fashion world. Her pictures are memorable, her body is perfect, her catwalk is fierce... How couldn't I like her? She became a celebrity too, and she makes Brazilians very proud. Gisele is very professional, and she's the biggest model we have ever seen IMO. Now she's really worried about the environment, so she's doing a lot of things to help to preserv our planet. I read a lot of interviews with her, and she seems to be really intelligent, nice, smart... She's also a businesswoman and almost an actress, I just love her!
Raquel Zimmermann: she's the current number 1 of MDC rank. I like her because she's not exactly the most beautiful model, but she's very professional and nice so she's the real proof that modeling is not only about being beautiful, you must be professional, polite and nice too. She's a symbol of longevity, she has never gone out of the top. I also like her poses, and her personality, because she's a simple person (when she was in Brazil during the SPFW, her agency provide an exclusive backstage for her, but she said it wasn't necessary!). She can go futher and I'm sure she will!
I can't say all the sucessful Brazilian models, because there are too many!