For me, it's Cole & Bunch's Sten, Herbert's Dune, McCaffrey's FSP setting, of late also Firefly, Riddick, Bujold's vorKosiverse, Just about every Errol Flynn movie ever made.
Other influences less prevalent but still important: Starship Troopers, Niven's Ringworld and Smoke Ring, Doc Smith's Fuzzy series and Lensman series, Battlestar Galactica (Original series), Buck Rodgers TV Series, Star Trek TOS and TAS, Alfred Thayer Mahan's The Influence of Seapower Upon History, Lots of USN manuals, Hitchhiker's Guide to the Galaxy, several of Arthur C. Clark's novels.
Note: I found Asimov's Foundation impossible to read... I've tried with several different novels.