Perimeter Defense

This one has a lot of empire building and grand strategy in it -- sort of like the main character stuck in a virtual Eve Online who's is responsible for saving the human fleet from an alien threat. So for your sci-fi fix, this one might do the trick. The protagonist, a professional gamer in Russia, is offered a new job to unofficially play as another gamer's character in a beta game. He accepts this new job and finds he's unable to log out.Despite having some of the same trappings as other LitRPG's, this series is unique to the genre. The emphasis is on the character gaining reputation and wealth and using such to build up a fleet/empire to dominate with and not slaying monsters, acquiring stat points, and trying to sleep with NPC barmaids. Even more, the protagonist, unlike most of the wish-fulfillment LitRPG in the genre, occupies the body of an old, fat and hated prince rather than a perfect digital specimen.The series is a bit of a hit or miss with the character blithely conquering all and sunder with barely a hitch, but because this one is quite a bit different than the usual run of the mill LitRPG, I recommend it -- especially for those who want more focus on military strategy.