I looked through the games on my shelf, and thought about the games that had appealed past and present, and I think I have to go with Margaret Weis Productions. Despite my lack of enthusiasm for most of the Cortex Plus lines, I’ve been using Cortex classic since Serenity came out, then locked in on the Battlestar Galactica/Supernatural/Cortex Core version once it was released. It’s easily my favorite set of mechanics. Funnily, even though I don’t particularly like most versions of Cortex Plus — from the odious Smallville to the meh Leverage, I am somewhat fond of Firefly and think it would handle both Star Wars and Star Trek better than it does the ‘Verse.