It's going to be a close call this year, especially versus last year where Sony was the clear cut winner to me - but things change.
It really depends on what kind of games do you like. To me It's like this:
Alan Wake vs Heavy Rain
Mass Effect 2 Fable 3 vs pick the top PS3 exclusive RPG this year and It's runner up to be fair.
God of War doesn't really have a equivilient. Well I guess Dante's inferno is but, meh..
AAA exclusive of Halo Reach vs Gran Turismo - Do you want a awesome racer or a awesome FPS? I'd say It's a tie for that.
Joy Ride vs Mod Nations? I guess?
Third party support/exclusives - They seem to be both pretty even.
Downloadable games - I've yet to see a year where the PS3 has really destroyed with PSN vs XBLA downloads. XBox Live Arcade has always had a good edge, and I'm sure this year won't be any different especially if the Castlevania game ends up being exclusive.
Then theres the whole Kinect vs Playstation Move. I'm going to side with Kinect despite my dis-interest in all the titles. Why? I already got a Wii and putting it in HD just doesn't do enough for me.
I'm giving a solid edge to the 360 for now. Sony could have made the competition a lot closer by releasing Infamous 2, Killzone 3 and Twisted Metal all this year but they delayed them to next year. 2011 is going to be tough with all those titles along with the rumored Uncharted 3. It's pretty much just a matter of waiting on reviews now because we know what the rest of this years line up will look like baring any last minute surprises (where are the damn RPGs?)