Mass Effect very closely followed by Uncharted and then Assassins creed.

I love Gears, but Mass Effect is too full of awesome. M.E. all the way for me.

It saddens me that I have never tried Professor Layton or the Pheonix Wright games. Need to fix that issue, soon.

The best new IP this gen would have to be Uncharted. It is, well perfect. After Uncharted, I would say:

Gears of War
No More Heroes
and, LittleBigPlanet

For me it's Mass Effect. Great story and good gameplay.

I also liked Assassins Creed, Borderlands, Saints Row... and Endless Ocean.

Both series are excelent, with Layton being just tad better.

The main issue with Wright, is that you have to finish all 3 of them to fully understand the story.

You should get them, Layton 3 will easily make you shed a tear.

Would a close call for me between Assassin's Creed and Mass Effect. Mass Effect probably just gets it, as its left in greater suspense.

My favourite completely new IP is Uncharted

but my favourite series that are new but not technically new IP's are Fallout 3/New Vegas (never been on a console before this gen) and the Modern Warfare spinoff of Call of Duty (mainly just b/c of CoD4).

Uncharted is number 1 for me with Assassin's Creed and Mass Effect tying for second.

There have been so many awesome new franchises this gen, but as for a favorite it would go to Gears of War. So many hours sunk into this game and great times playing with friends; it's unforgettable.

Honorable mentions:

Mass Effect
Assassin's Creed
Left 4 Dead
Portal
Bioshock
Dead Space
Batman:Arkham (If it counts)