Let's break it down (while trying to keep Yahoo's mainstream audience in mind):
- Wii Resort great choice, since it'll probably become the best selling game of 2009
- Bioshock 2 BioShock was great, but we've hardly seen anything of this game
- The Sims 3 another big mainstream release which clearly belongs on the list
- Call Of Duty: Modern Warfare 2 sure, CoD still is the biggest FPS franchise atm
- Resident Evil 5 yep, Resident Evil is still big and RE5 looks to be turning out great
- StarCraft 2 SC is still one of the biggest RTS franchises, and it's the next big Blizzard release
- God of War 3 provided it makes 2009, of which I'm doubtful
- Grand Theft Auto: Chinatown Wars well, it's GTA and it's on the NDS, so prolly good choice
- Halo Wars Yeah, it's Halo, though Halo 3: ODST might be bigger
- Puzzle Quest: Galactrix Hmm nope, doesn't really belong here
- Wolfenstein Wolfenstein is probably too old skool and the game isn't looking too hot right now, so no
- Brutal Legend It has Jack Black and rock music, so it has more sales potential than Psychonauts at least
So I'd scrap BioShock 2, God of War 3, Halo Wars, Puzzle Quest and Wolfenstein, and replace them with any of the following:
Uncharted: Among Thieves
The first game didn't set charts on fire, but it did gain momentum in the months following release. Due to word of mouth and a further developed gameplay model, Among Thieves has great potential to become one of the biggest releases of 2009 (they've shown more footage of it than of GoW3 at the very least).
Killzone 2
The buzz among gamers created by the beta has been great and to this day, it's still one of the most impressive looking games. Seeing how there aren't many other big FPSes coming out this year (right?), KZ2 looks set to satiate most FPS nuts' needs.
Heavy Rain
Provided it manages to live up to it's many promises, this could easily be one of the biggest releases of the year. Even if it doesn't live up to everything, it's still an impressive looking game with an interesting premise and great atmosphere, with quite a bit of mainstream potential as well.
Street Fighter IV
From the very beginning, SFIV was designed to appeal to a broad audience, and bring back old skool SFII fans, while still maintaining enough gameplay depth to satisfy hardcore players. It's the first mainline SF release in ten years time, which in itself is very big.
Alan Wake
This game has been in development for quite a long time now, but a recent trailer seems to indicate the game is getting along fine now and is still very impressive looking. Even after all these years, this title still has lots of potential to make a big splash in the gaming landscape.
Tekken 6
It probably still is the most popular fighting franchise of the moment, and as such it's newest entry should be on this list. Also, just like SFIV, it has been playable in arcades for quite a while now, which also creates more buzz for it's console release.
Halo 3: ODST
Well, this might not be a full featured new release (or maybe it is?), but being a FPS, it still has far more sales potential than a console RTS like Halo Wars ever could. Halo 3 is still very popular anyway, and ODST could inject it with some fresh blood.
Mafia II
Highly overlooked at the moment, but I feel it has much potential to become one of 2009's biggest and best releases. It all depends on the marketing. Mafia is still considered by many PC enthusiasts as one of the best games ever made, especially due to it's fantastic atmosphere and storytelling, which gives the lauded GTA series a run for it's money. If Mafia II upholds those qualities, it will be loved by many.