Four games that have, in my opinion, awesome settings.
1. RIFTS- We all know the setting. Post-Future-Apocalypse sci-fi with magic and aliens and demons and every-goddamn-thing you can think of. The rules problems are well known and well mocked throughout the land.
2. In Nomine- Modern day angels vs. demons. God is absent, Lucifer is indifferent, so the Archangels and the Demon Princes wage war on each other. Add to the mix sorcerers, undead, humans with an array of divine or infernal powers, and the remnants of the pagan gods living in the collective dreamscape of humanity. The game oscillates between very dark and very funny. The rules system is based around a novelty die mechanic that wears thin. The rules system also assumes angels/demons as the baseline PCs, and thus creates a scale where ordinary humans are utterly useless, and even supernaturally empowered ones are kind of lame.
3. Tribe 8- Post-apocalyptic fantasy horror, with humanity slaving away under bizarre and tyrannical living goddesses who saved mankind from weird icky fleshy fetish alien/demon things that had previously subjugated our entire race. Add in weird technology priests, mutant barbarians, and a tribe of exiles who follow a slain god. Highly inspiring, if somewhat overwrought. Bizarre dream magic and weird ass anime powers based on what particular god you used to belong to before you got kicked out of civilization. The rules system is one that I hate maybe more than any other I've ever played, ever since we played Gear Krieg (dieselpunk World War I using the same rules) and found that headshots and flamethrowers are insufficient to kill enemies in combat.
4. Fireborn- Magic is reawakening in the modern world and creatures of magic are returning from their slumber. Players are dragons who are reincarnated as humans. As they reawaken, they gain sweet ass dragon powers. They have to contend with various supernatural entities, all of whom seem to have beaten the dragons in the whole waking up process...
Players also make a second character: full on, godlike dragons, that they play in flashbacks to an ancient mythic era before modern history. Neat in that the flashbacks are how you learn new powers as a human. The combat system is novel and is kind of reminiscent of Tekken. (You set up moves like Punch-Punch-Duck-Kick or whatever.) I found the rules to be a bit clunky.
RIFTS- Currently working on retro-fitting RIFTS to AD&D. The Palladium system started off as heavily house-ruled AD&D, after all.
In Nomine- Right around the time I graduated college and moved here, I was working on a FUDGE conversion for In Nomine. Sadly, I lost the notebook in the move and was never motivated enough to finish my translation. These days, I think the "New" World of Darkness (I hesitate to call it new because I think it is seven or eight years old now...) would actually be a better fit. (Plus, converting something to FUDGE is kind of a pain in the ass, more so than the usual conversion process)
Tribe 8- I was also working on converting this to FUDGE right around the time I was converting In Nomine. Unfortunately, the notes were in the same notebook. Bummer.
These days, I'm thinking Savage Worlds might be a way to achieve the cinematic feel the developers seemed to be going for, but that the Silhouette system just couldn't seem to deliver to me. Also, the power system in Savage Worlds might be better for emulating the weird ass power and magic system from T8.
Dragonborn- I think of this game as a weird cousin of World of Darkness, so I'd totally convert it to NWoD. I'm not sure the element-based stats would map well to NWoD, so essentially I'd just be taking the concept and trying to fit it to entirely new mechanics.
My gawds, what is wrong with me?