Marvel does indeed have an RPG system mapped. Played it once... wasn't very captivating, but I think that was more to do with the fact that the GM had prepared a lousy adventure. Mechanics held up OK.
Vampire: The Masquerade is brilliant if you have a good GM who knows his/her way around the setting and can bring the diverse and nuanced vampire society to life, and especially long-term-oriented plot arcs can be immensely satisfying.
Arcane Codex is a pretty standard affair in RPG terms, but I still find it more appealing than D&D when it comes to fantasy roleplay.
Now, for some detailed recommendations:
If you're into superpowers and a novel roleplay experience, you should find Wildcards decidedly more interesting.
It's based off the Mutants and Masterminds RPG template and concerns an alternate reality wherein shortly after WW2, an alien virus bomb hit New York that caused spontaneous radical mutation. The virus's effects (which slowly spread across the globe since the virus is airborne) were categorized in a system based on playing cards; 90% of victims drew the Black Queen (they died), 9% drew the Joker (they mutated into deformed creatures) and 1% drew an Ace (they remained normal-looking and got some kind of superpower). There are also in-betweeny categories, such as Jokers with superpowers and Aces with useless powers (like growing bodyhair at will). As one would expect from a game whose timeline starts in the late 40s, Jokers became the new blacks and were forced to live sequestered from the rest of New York in a ghetto called Jokertown, while Aces had a brief heyday with a well-known team of superheroes before being stigmatized during the McCarthy era; as things stand today, life is only marginally less wretched for the average Joker, and anonymity is any Wildcarder's best friend.
All in all it's a well thought-out alternate reality setting, using real historical figures and taking a realistic approach to mature themes (like violence and sex)... not much of a surprise, considering one of the co-creators is George R.R. Martin.
In our RPG group I'm the GM for any of the Warhammer 40.000 games, which can be pretty damn cool if you're into the setting. I haven't played Rogue Trader myself, since nobody was interested in gritty versions of Han Solo, but Dark Heresy (wherein you play an acolyte of the Inquisition) allows for wonderfully varied roleplay somewhere between detective work, dark tales of suspense and exciting combat. Black Crusade serves as a kind of dark mirror to DH, casting your players in the roles of a warband of Chaos worshippers and renegades, and is also very good. Deathwatch can be a lot of fun as well, but make sure your group is into Space Marines if you want to go for this one; since Space Marines are somewhat set in their mannerisms, the roleplay is somewhat constricted, but the action is still cool. The game system is a variation of the standard d100, and the books offer detailed descriptions, pictures and tables galore with good order and structure.
Another good one is Unknown Armies. If you're into mindfuckery, this is the game for you! Your players take the roles of plain human being, avatars or magical adepts.
Human beings can navigate their way through plots without powers and disadvantages connected to those powers. Avatars draw their powers from conforming to an archetype present in the collective subconscious of the world (e.g. the Mother, the Messenger, the Warrior, the Merchant, the Child, the Fool etc.). Magical adepts can perform magic connected to their specific school in the Underground; basically, these people are completely insane and believe so strongly and obsessively in their demented version of reality that they actually make it come true. For example, Dipsomancers know that the truth is found at the bottom of a bottle... they're basically telekines who draw their power from getting (and remaining) plastered, with a higher state of inebriation resulting in the ability to perform ever stronger feats of magic.
The plots are mostly based around mystery, intrigue and intersecting/overlapping layers of reality and range from anywhere between werid and madmadmadmadmadmadmadmaaaaaaaaad. Again, this is the game for you if you enjoy a good mindfuck.
The last game I'd like to recommend is The Laundry. You play as an agent of the titular secret British government organization tasked with regulating paranormal/extradimensional activity on Earth and making sure the Ancient Ones can't grab a foothold in our reality. Think Men In Black with a Lovecraft spin, spiced with a hefty dose of bureaucracy and dry British humour.
