All Points Bulletin was easily the biggest bomb of the year.  That game apparently took close to $100 million to make and the game was axed shortly after release.  Realtime Studios was also closed after this huge flop of a game.  The game was so bad that it was actually sold for 1.5 million pounds-- talk about a loss of investment.  With an average metacritic score of 57, no other game mentioned in this thread has flopped as hard as APB.

Also, I would say say that 2010 is easily the year of HD flops.  The Wii isn't the only system with lots of flops.  Other notable games that haven't been mentioned:

1.  DefJam Rapstar- A game that hyped to help re-invigorate the music industry has only sold 160K combined on 3 systems

2.  Splatterhouse- This game is not off to a good start and has only sold a combined 70,000 after 2 weeks.

3.  The Force Unleashed 2- This game isn't exactly a bomb, but its numbers are incredibly down compared to the 1st game. 

In terms of quality of the game and more broadly the former quality of the franchise I'm going with Metroid Other M.

In terms of Sales unfortunately I'm going with Red Steel 2. Love the game, but it just did not do well.

DEFINITELY FF14!

Guys, Epic Mickey and Grand Turismo 5 are not bombs.  Epic Mickey will likely sell a million off of US sales alone, even with the disappointing EMEAA debut.  And GT is on track to do some healthy numbers as well.

The biggest bombs to me due to clearly not meeting expectations were Blur, Metroid: Other M, and  the biggest this year is Final Fantasy XIV easily.

In terms of MMO's, yeah, FFXIV and especially APB bombed hard.

Prince of Persia easily. It sold like 200k across 3(edit 5 including DS and PSP) platforms and can be bought for $10 regularly during this holiday season.

Its one of those bombs that is actually pretty good too. Well, at least the Wii version dunno about the other two systems.It well worth $10 I paid $20

I disagree, both GT5 and EM were expected to do gangbusters, I do remember some posts saying GT5 was a lock for 10 million and EM would do 5 million easily and what have you. So yes, compared to expectations, they bombed, much like another game you like to defend so fiercely :P

lol people saying FFXIV is the biggest haven't heard of APB it seems.

In terms of money lost, FFXIV probably wins, just that Realtime Worlds had far less money to lose before they were forced to fold entirely

Hopefully Square Enix doesn't sink too too much into this, otherwise they'll have to merge with Bandai Namco and Tecmo Koei to form the Japanese Game Company xD