Here's what I would do:
Don't disclude Wii/DS games. That eliminates some marquee titles, like Mario and Sonic, MySims, and Rabbids 2. Also, don't include titles like Namco Museum, DDR, or even the Tycoon game which get churned out all the time and are simply getting some interesting Wiimote additions. Don't include WarioWare and Wii Play, which simply debuted in NA late, but were otherwise launch titles. No Japanese stuff that may or may not make it to the West this year like Fire Emblem or DQ:S. No lame, third-string Nintendo projects like DK Jet, Kirby or Mario Party 8.
Where does that leave us?
Sonic and the Secret Rings
Cooking Mama
Super Paper Mario
Big Brain Academy: Wii Degree
Pokemon Battle Revolution
Mario Strikers Charged
Metroid Prime 3: Corruption
Dewy's Adventure
Carnival Games
MySims
My Word Coach
Brothers in Arms: Double Time
Battalion Wars 2
Boogie
EA Playground
Mario and Sonic at the Olympics
NiGHTS: Journey of Dreams
No More Heroes
Super Mario Galaxy
Super Smash Bros. Brawl
Wii Music
Rayman Raving Rabbids 2
Wii Health Pack
Resident Evil: Umbrella Chronicles
24 titles that I think are interesting. Pretty wide-ranging lineup, too, though much heavier on "casual" than "hardcore." At least 4 of these will be bumped to next year, making it 20 titles. :D
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.