Classics: Strugatsky brothers of course. My favorite is "Monday starts at Saturday". Also there are some classics from 1920s like Belyayev and Alexey Tolstoy. Also Ivan Yefremov is considered classics but his books are too boring for me. From the modern writers I like early works of Sergey Lukyanenko. I didn't like his most recent books though. Btw, Ramil translated the whole Lukyanenko NOVEL (not the best one imho) into English here at this forum:

S. Lukyanenko. The Dreamline . Proofreaders are welcome )))