Hmmm...well Left4Dead certainly is different from the norm.
Natural Selection 2 (if it ever gets released) will be unlike anything you have ever played before.
Battlefield Heroes is pretty innovative, especially in terms of business model.
STALKER and STALKER:Clear Sky were simply fantastic games, if buggy, that delivered a unique setting and style of play.
The above games are all examples of innovation within the genre. But while 'innovation' is good, 'originality' doesn't really exist (or matter), for example:
Quake:Live certainly isn't original but its got standard mechanics done to perfection - who needs this false concept of originality (and it is false, as everything is based on or influenced by something) when you can have pure unadulterated fun?