Well that's easy...
Coming up:
Little King's Story: Pikmin-style gameplay with a dark sense of humor.
Wii Sports Resort: 1:1 swordfighting+archery. Live those Kurakawa films!
Fragile: Crappy gameplay, but beautiful atmosphere and music.
Shiren 3: Fun roguelike RPG. Now a little less frustrating because you don't lose your levels upon death...but only a little. 
Resident Evil Darkside Chronicles: Umbrella Chronicles plus RE2=win.
Rabbids Go Home: An adventure game from Ancel, the genius behind Rayman and Beyond Good & Evil. The Rabbids are finally going to be used as he intended them to be: in a humurous non-minigame.
Tales of Graces: The dude's who made the original Symphonia and Vesperia are making a new game revolving around a time-traveller from the 70's. What more do you want?
JU-ON: A haunted house simulator from the dude who made those famous Japanese horror flicks. Should be a fun rental.
Sin & Punishment 2: The first sequel I can think of from Treasure.
Mario platformers: No introduction needed.
Monster Hunter 3: ARPG (sorta) co-op gameplay. Show Dr. Grant how you really take down a dino!
The Grinder: Have you played Left 4 Dead yet? HAVE YOU?!?!
Silent Hill Shattered Memories: The remake of the original (scary) Silent Hill, mixed with Clock Tower's game mechanic. Emphasizing the horror in survivor horror (I hope).
Red Steel 2: Cel-shaded cowboys with swords.
Sam & Max: Season Two: Everyone's favorite talking dog and rabbity-thing go on even more adventures!
Tatsunoko vs. Capcom: It's the latest in the Capcom vs. series, and supposedly pretty awesome. And it may have online!
Metroid Prime Trilogy: Because you REALLY need to play 1 and 2.
Chibi Robo: A charming and overlooked Gamecube game that you're probably not going to find on its original system.
Beatles Rock Band: ....'tis the Beatles, man.
No More Heroes: Desperate Struggle: Do you like violence? Do you like goofiness? Do you like having two lightsabers, and fifty bosses to use them against? Do ya?
Trauma Team: From the folks who've been making those Trauma Center games. Speaking of which, why haven't you played them yet?
Cave Story: One of, nay THE finest indie game ever made, updated, expanded, and only ten bucks.
FFCC: My Life as an Overlord: MLaaK was a surprisingly solid game. MLaaO promises to take the universe and turn the roles on their heads. Puts a new meaning to the phrase Tower Defense.
Tales of Monkey Island: From Telltale Games (Strong bad, Sam & Max, Wallace & Gromit) comes entirely new episodes in the classic point-n-click games, Escape from Monkey Island.
Bit.Trip:Core: Now even tougher than Bit.Trip:Beat! Same guys, same rhythm based balls-busting, different gameplay.
FF IV: The After Years II: Gotta finish what Squeenix started.
Night Game: Look it up. Love it.
Probably missing a few. Virtual Console games omitted. Will add released titles if you're interested.