Which system(s) are you itching to play but haven't yet?
Whether it be due to scheduling, lack of interested players, or some other reason, what's an RPG system you're just hoping to get to the table one of these days but haven't been able to yet?
Black Star. This is a new game, so not too many people are aware of it. I'd consider this a rules light Star Wars game.
White Star. Despite the similar names, it's made by different people than Black Star and the mechanics are wildly different. However, I'd also say this is Star Wars-esque sci-fi.
There are also a couple Savage Worlds sci-fi settings that look neat, like Titan Effect and Interface Zero. I feel like I'm missing a big sci-fi game I really want to play, but I can't think of it off the top of my head.