I feel from my experience giving recommendations to people that knowing what they dislike is almost as important.
Anyway, I prefer fantasy to sci-fi but am a voracious reader of both.
I love everything Roger Zelazny.
I like Glen Cook's The Black Company and A Cruel Wind (hadn't tried his sci-fi yet).
I absolutely love Vernor Vinge's A Fire Upon the Deep.
I am eagerly awaiting the third part of The Kingkiller Chronicles.
I've read almost every single Discworld novel. Most more than once. Some more than 5-6 times (especially Vimes's books).
I don't care for Tolkien and Stephenson.
I don't care for fan-fic style and quality writing (Naomi Novik in fantasy, Jack Campbell's The Lost Fleet as an example in sci-fi).
I'm going to say Zen Cho's Sorcerer To The Crown. Zen Cho loves Jonathan Strange and Mr. Norrell, and is happy when her book is compared to it. I also compare her book to it, when I say it's like Strange and Norrell, if Strange and Norrell wasn't boring as hell. And if it was funnier. And smarter. And sharper. It is both a super fun Regency pastiche and super smart social commentary all in one great package.
I'll have to check it out! I like Jonathan Strange and Mr. Norrell a lot, and I disagree with you that it was "Boring as hell." (and that's why I can't read Stephenson and Tolkien) The first 100 pages and the last 100 are a bit of a slog, but it's incredibly sharp and engaging in between.
I also hope you've read the book in English. It's one of those that no translation can do justice.