I usually like Niven and Pournelle’s stuff, and particularly recommend The Mote in God’s Eye for a great first contact encounter. There’s a sequel The Gripping Hand which is not as great, but still worth the read.

Started on Name of the Wind by Patrick Rothfuss. A lot of people say they like this one. Not far enough into it yet to say if I agree with them, but it looks like there’s some detailed worldbuilding which is a good sign.