I liked the first Infamous, but I never played the second because so many people here were down on it when it came out.
Yes, quite honestly, this question couldn't be any easier. Titanfall to me is a true rethinking of the modern FPS, and I think it's a brilliant game. It genuinely makes other FPS feel kinda boring when I think about them, and I've been a huge COD guys for years now. I'll probably still play COD going foward, but Titanfall has definitely reset my expectations for how interesting the gameplay can be.
Two things:
1) Games like GTA and Uncharted are doing some exceptional things. GTA does open world cities like no other game. It does incredible characters, and crazy vast gameplay possibilities, with all the vehicles it offers, etc. Uncharted does cut scenes, voice acting, and story telling on an exceptional level. It also has incredible graphics and very good gameplay IMO. So you can do more of the same when the entire package is exceptional, even still, quite a few people complained after Uncharted 3 that the formula was wearing a little thin. Now we've got a third Infamous game, and that's from a franchise that hasn't really hit the high points that Uncharted has.
2) There are rarely true "revolutions" in gaming. But sometimes you do see games like Titanfall doing something really new in a genre. That game does FPS player movement, mech movement, and game design exceptionally well.