PS3, its not even close to a question. Past 3 years Sony has bitchslapped both Nintendo & Microsoft in first party releases. 2011 alone proves this where PS3's library destroyed the competition by a huuuge margin.
1.Most IPs (new & old)
2. Most releases in past years
3.Easily most variety
4. Usually best graphics on market :P
5.Tons of GOTY reviews
Yeah, its no contest