Good for you for branching out! I'm a classic sci fi/fluff fantasy fan, myself, but I've read all of the Holmes stories, plus several about him by different authors (non-cannon, of course *grin*), and a lot of other things thrown into the mix. Nothing is quite like our friend Sherlock, of course.
I'm not sure exactly what you are looking for, so here are some suggestions that I put together. It was hard not to write more! I love books. *grin*
Mansfield Park was my least favorite work by Jane Austen. I would suggest reading either Emma (my favorite, but a bit unusual for her), or Pride and Prejudice, both of which are definitely better books. But yet, you don't say you actually enjoyed Mansfield Park at all, so perhaps her writing isn't your favorite anyway.
I just read Peter Pan, by J.M. Barrie. It was amazing. Nothing like the Disney film, but better, even. Classic children's books are usually a good place to explore for interesting reads.
I would suggest "Daughter of Fortune" by Isabel Allende, which is a fiction novel that takes place in Chile and California the 1940s. Loved this book, and it's a good read if you are trying to read authors that are not native English speakers, too. Gabriel Garcia Marquez's "One Hundred Years of Solitude" was also amazing, but long and a bit depressing.
For the Detective/Mystery genre:
Dorothy Sayers - Any books in the Lord Peter Wimsey series are absolutely necessary for someone who loves a good detective novel. This lady was one of the very first commercially successful women detective novelists. The story of her life is pretty interesting, too, but the books are just awesome.
Rex Stout - He created a series of mysteries involving a detective by the name of Nero Wolfe, which starts with the book "Fer-de-Lance." I haven't read them in years, but there were pretty solid detective novels, if memory serves. A lot of friends recommend this series.
Non-Cannon Holmes:
"The Beekeeper's Apprentice" by Laurie R. King. The whole series was suggested by another person. These books are based on Doyle's Sherlock Holmes, but King put her own twist on the character.
"Good Night, Mr Holmes" by Carole Nelson Douglas was excellent. Another author's take on the Holmes character.
A couple of really strange non-cannon Holmes book are Fred Saberhagen's "The Holmes-Dracula File" and "Sherlock Holmes in Orbit," which is a collection of science fiction short stories about Holmes edited by Mike Resnick and Martin H. Greenberg.
Also, you should really take a look at some classic sci fi while you are at it, since you call yourself a new age science fiction fan. Good ones include: Anything by Isaac Asimov (especially his short stories); "Fahrenheit 451" and "The Martian Chronicles" by Ray Bradbury; "Nor Crystal Tears" by Alan Dean Foster; "Dune" by Frank Herbert; "The Best of C.M. Kornbluth" which is an anthology of short stories Kornbluth wrote, edited by Frederik Pohl; "Ringworld" by Larry Niven; and "The Steps of the Sun" by Walter Tevis. There are so many I could say!
Some Fantasy good ones, for fun ;) -
"The Riddle-Master of Hed" by Patricia A McKillip (plus the rest of the trilogy); "Lord Valentine's Castle" by Robert Silverberg; and "The Princess Bride" by William Goldman.