10) Searing Rays: this has serious potential to be unbalanced in your favor. Nice finisher, I've dealt 22 damage with this spell in Chaos.
9) Dual Lands: perfect lands for long multiplayer games where people usually won't bother to spend tons of money on the real things.
8) Kavu Titan: this guy is powerful and versatile. Will see play in T2 and casual, also in Spike decks where you can move counters around
7) Aura Shards: I don't know if people realize how powerful this card is. It will take 2 weeks for this card to be restricted in my group play. And its uncommon.
6) Elvish Champion: Goes up many spots because of the killer artwork. But the card is good too.
5) Void: This card is bad-ass. It loses points b/c its gold, but I can understand why.
4) Fact of Fiction: The best blue search card/drawer in a long, long time. This one is getting proxided right along with my Sol Ring and Zuran Orb. When I get some that is.
3) Psychic Battle: Casual play written all over it. Fun card, I dig it.
2) Undermine: hmmm, tasty counter spell. Nice addition to B/U creatureless decks.
1) Mage's Contest: I love this card, I want this card. I hate you Story Circle, Douse and all the like.
WORST CARD: Loafing Giant: "Duh, I'm a rare because, well uh, I'm not sure either."
Most underrated commons:
Dream Thrush, think of it this way:
1U, Flying, 1/1
TAP: Target land produces 1 mana of any color OR any creatures you control with landwalk can now do their thing OR Maze of Ith is now useless OR your City of Brass won't deal damage to you any more OR.....
Traveler's Cloak
Cantrip: Possible game breaker. Me like pretty blue cards.
Quirion Sentinel
Although he isn't quite a 2/1 for G, he is damn close to being one. He can be used in beatdown decks and combo decks. Nice little creature.
Recoil
OK so its not underrated, but it is very very good. Good on its own, best used with discard to get rid of artifacts and enchantments.