My favorite at the moment: Ready Player One by Cline (the movie should be out soon, wahoo!). Some older ones by Heinlein come to mind, like Starship Troopers.

I've ran across several science fiction ebooks that are in 1st person. They're definitely not in the majority, but I enjoyed them. The ones besides the above that stuck in my mind the most were the books with a bit more humor or a bit more a silly (but enjoyable) plot than most. Eat Fish and Die, Stray by Host, Bob Moore: No Hero (a bit of superhero -- fantasy or sf? maybe it depends on the hero).