Eclipse Phase - It really opens up the flood gates to letting players and GM's explore what it means to be human. The books they are based (VEEERRRRRRYYYY loosely in a timeline sense, the Stack sense very closely) is Richard K Morgan's Altered Carbon which is absolutely a must read.
Star Wars - I prefer the SAGA (d20 system) over WEG. While I do prefer non-class systems, SAGA does class systems very well in my opinion and you can make some very unique combos. I have run both systems and while I have a true liking of WEG, I found I had to house rule a lot of stuff. Beyond the 'Jedi and Mooks' problem that comes in WEG at a certain Character point (Karma) level, the wild die induced lethality which makes characters get insta-smeared or on the 6d6 strength (Looking at YOU wookiees) side of things unkillable machines just makes for too many oops.
Mass Effect (Using SAGA) - I've made a home system for the Mass Effect universe using SAGA. It works rather well, though like any true adaptation is a contant work in progress. My players have love it. I'd love to play it, but that's the impossible dream.
DC Adventures (M&MM 3e) - I have found I love this system and for more than just superheroes. The combat is dynamic and smooth. The power level 'sliders' (Where you can be super accurate, but low damage, or high damage, but not that accurate) allows for good flavor while keeping the playing field nice and smooth (within a set powerlevel. A higher power level character is just...more.) The system just...works.
Dresden Files - Awesome setting, awesome RPG books, fun system. One of my favorite thing about the Shadowrun novels is the immersion the reader gets into the world. It's not a boring tomb of lore like we're chewing through someone's graduate thesis, but we're being exposed to snippits of datafiles with commentary from in game characters voicing (potentially misleading) ingame opinions. Dresden Files is written as an In World RPG by Billy (A major character in the series) that is about to go to the final production stages soit has margin notes by Billy, Bob and Harry as they have in character commentary about stuff. It's very well done for making it an interesting read and keeping the reader in the right mindset.