I'm fond of "A Fire Upon the Deep" by Vernor Vinge, and its kind of prequel "A Deepness in the Sky", they both contain some great ideas and I love the fact they have some very alien aliens!
Oh and if you haven't read any Douglas Adams "The Hitchhiker's Guide to the Galaxy" is fantastic
Oh and if you haven't read any Douglas Adams "The Hitchhiker's Guide to the Galaxy" is fantastic