5. Star Trek Online
I’m going to start this off with a disclaimer: I worked on Star Trek Online. That said, when STO launched, it was, in a word, crummy. It had (and still has) a wonderfully fulfilling space-combat section, which was supposed to be supplemented with a bad-ass away-team/ground combat mechanic. Unfortunately, the ground-combat aspect of the game turned out to be boring, repetitive, and pretty unbalanced.
MUCH has changed since STO launched in 2010. The game has heaps (read: HEAPS) of new content. Dozens of hours of space and ground combat, an enormous galaxy to explore, an interesting (if not well delivered) story line, tons of canonical original content which Star Trek fans will absolutely love, and a surprisingly large amount of genuinely fun multiplayer PVP and cooperative PVE missions. The ground combat is still rather clunky, but they’ve balanced it out a great deal, added tons of new abilities, and since at least 60% of the game takes place in space anyhow, it won’t be that much of a bother. Considering STO is free, you should really take the time to check it out. Star Trek fans in particular have absolutely no excuse to miss this game.