i have 21 platinums and Motorstorm Pacific Rift is the one i feel more proud of having hands down!! ( some of the races took me more than good drving and luck to beat them lol ) , honorable mention Sly Cooper 3 : Honor Among Thieves
I only have 8 and 4 are for God of War titles, and I only need one more for Ghost of Sparta. I have both inFAMOUS ones and I finished Festival of Blood %100, I have X-men Origins: Wolverine, and Sonic & Sega All Stars Racing. Too bad I can't get one for inFAMOUS: FoB.
Im going to have to say Cross Edge it was a nightmare, because when I actually completed it i had to redo it because there was a glitch with getting 2 trophys back to back The Hikikomori and the Crossover Conquest(Platinum) was glitched if you got them at same time.